15915994 has 12 divisors (see below), whose sum is σ = 24540894. Its totient is φ = 7741584.

The previous prime is 15915979. The next prime is 15916001. The reversal of 15915994 is 49951951.

It can be written as a sum of positive squares in 3 ways, for example, as 15499969 + 416025 = 3937^2 + 645^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 15915994.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 169 + ... + 5644.

Almost surely, 2^15915994 is an apocalyptic number.

15915994 is a deficient number, since it is larger than the sum of its proper divisors (8624900).

15915994 is an equidigital number, since it uses as much as digits as its factorization.

15915994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5889 (or 5852 counting only the distinct ones).

The product of its digits is 72900, while the sum is 43.

The square root of 15915994 is about 3989.4854304785. The cubic root of 15915994 is about 251.5424320424.

The spelling of 15915994 in words is "fifteen million, nine hundred fifteen thousand, nine hundred ninety-four".