15617681 has 2 divisors, whose sum is σ = 15617682. Its totient is φ = 15617680.

The previous prime is 15617671. The next prime is 15617683. The reversal of 15617681 is 18671651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13808656 + 1809025 = 3716^2 + 1345^2 .

It is a cyclic number.

It is not a de Polignac number, because 15617681 - 2¹⁴ = 15601297 is a prime.

It is a super-2 number, since 2×15617681² = 487823919635522, which contains 22 as substring.

Together with 15617683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15617683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7808840 + 7808841.

It is an arithmetic number, because the mean of its divisors is an integer number (7808841).

Almost surely, 2^15617681 is an apocalyptic number.

It is an amenable number.

15617681 is a deficient number, since it is larger than the sum of its proper divisors (1).

15617681 is an equidigital number, since it uses as much as digits as its factorization.

15617681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 35.

The square root of 15617681 is about 3951.9211783638. The cubic root of 15617681 is about 249.9609592369.

The spelling of 15617681 in words is "fifteen million, six hundred seventeen thousand, six hundred eighty-one".