15987913 has 2 divisors, whose sum is σ = 15987914. Its totient is φ = 15987912.

The previous prime is 15987901. The next prime is 15987931. The reversal of 15987913 is 31978951.

Together with next prime (15987931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8573184 + 7414729 = 2928^2 + 2723^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15987913 is a prime.

It is a super-2 number, since 2×15987913² = 511226724191138, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 15987913.

It is not a weakly prime, because it can be changed into another prime (15987953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7993956 + 7993957.

It is an arithmetic number, because the mean of its divisors is an integer number (7993957).

Almost surely, 2^15987913 is an apocalyptic number.

It is an amenable number.

15987913 is a deficient number, since it is larger than the sum of its proper divisors (1).

15987913 is an equidigital number, since it uses as much as digits as its factorization.

15987913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 43.

The square root of 15987913 is about 3998.4888395493. The cubic root of 15987913 is about 251.9207412202.

It can be divided in two parts, 15987 and 913, that added together give a square (16900 = 130²).

The spelling of 15987913 in words is "fifteen million, nine hundred eighty-seven thousand, nine hundred thirteen".