15961865 has 8 divisors (see below), whose sum is σ = 19424448. Its totient is φ = 12589360.

The previous prime is 15961859. The next prime is 15961873. The reversal of 15961865 is 56816951.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15961865 - 2⁴ = 15961849 is a prime.

It is a super-2 number, since 2×15961865² = 509562268556450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 22127 + ... + 22836.

It is an arithmetic number, because the mean of its divisors is an integer number (2428056).

Almost surely, 2^15961865 is an apocalyptic number.

It is an amenable number.

15961865 is a deficient number, since it is larger than the sum of its proper divisors (3462583).

15961865 is an equidigital number, since it uses as much as digits as its factorization.

15961865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45039.

The product of its digits is 64800, while the sum is 41.

The square root of 15961865 is about 3995.2302812228. The cubic root of 15961865 is about 251.7838545112.

The spelling of 15961865 in words is "fifteen million, nine hundred sixty-one thousand, eight hundred sixty-five".