15990891 has 8 divisors (see below), whose sum is σ = 24367104. Its totient is φ = 9137640.

The previous prime is 15990881. The next prime is 15990899. The reversal of 15990891 is 19809951.

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

It is not a de Polignac number, because 15990891 - 2⁵ = 15990859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15990899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 380715 + ... + 380756.

It is an arithmetic number, because the mean of its divisors is an integer number (3045888).

Almost surely, 2^15990891 is an apocalyptic number.

15990891 is a deficient number, since it is larger than the sum of its proper divisors (8376213).

15990891 is an equidigital number, since it uses as much as digits as its factorization.

15990891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761481.

The product of its (nonzero) digits is 29160, while the sum is 42.

The square root of 15990891 is about 3998.8612128955. The cubic root of 15990891 is about 251.9363816479.

The spelling of 15990891 in words is "fifteen million, nine hundred ninety thousand, eight hundred ninety-one".