Number of the day: 2616

Felix Hausdorff was born on this day 152 years ago.

Properties of the number 2616:

2616 is the 694^th totient number.
2616 = 2³ × 3 × 109 is the 2236^th composite number and is not squarefree.
2616 has 3 distinct prime factors, 16 divisors, 3 antidivisors and 864 totatives.
2616 has an emirpimes digit sum 15 in base 10.
2616 has a triangular digit sum 15 in base 10.
2616 has an oblong digit product 72 in base 10.
Reversing the decimal digits of 2616 results in an oblong number.
2616 = 655² - 653² = 329² - 325² = 221² - 215² = 115² - 103² is the difference of 2 nonnegative squares in 4 ways.
2616 = 4² + 10² + 50² is the sum of 3 positive squares.
2616² = 1440² + 2184² is the sum of 2 positive squares in 1 way.
2616² is the sum of 3 positive squares.
2616 is a proper divisor of 653² - 1.
2616 in base 25 = 44g and consists of only the digits '4' and 'g'.
2616 in base 29 = 336 and consists of only the digits '3' and '6'.

The number 2616 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A026772: a(n) = T(2n, n-2), T given by A026769.
A064403: Numbers k such that prime(k) + k and prime(k) - k are both primes.
A092049: Numbers n such that prime(n) == -7 (mod n).
A165037: Consider the base-5 Kaprekar map n->K(n) defined in A165032. Sequence gives numbers belonging to cycles, including fixed points.
A165039: Consider the base-5 Kaprekar map n->K(n) defined in A165032. Sequence gives numbers belonging to cycles of length greater than 1
A206038: Values of the difference d for 4 primes in arithmetic progression with the minimal start sequence {5 + j*d}, j = 0 to 3.
A224492: Smallest k such that k*2*p(n)^2-1=q is prime, k*2*q^2-1=r, k*2*r^2-1=s, k*2*r^2-1=t, r, s, and t are also prime.
A254242: T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock diagonal sum plus antidiagonal minimum nondecreasing horizontally and vertically
A257426: T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock diagonal sum plus antidiagonal minimum nondecreasing horizontally, vertically and ne-to-sw antidiagonally
A326083: Number of subsets of {1..n} containing all of their pairwise sums <= n.