15319991 has 4 divisors (see below), whose sum is σ = 15327984. Its totient is φ = 15312000.

The previous prime is 15319981. The next prime is 15320017. The reversal of 15319991 is 19991351.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19991351 = 2011 ⋅9941.

It is a cyclic number.

It is not a de Polignac number, because 15319991 - 2²² = 11125687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15319981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 791 + ... + 5591.

It is an arithmetic number, because the mean of its divisors is an integer number (3831996).

Almost surely, 2^15319991 is an apocalyptic number.

15319991 is a deficient number, since it is larger than the sum of its proper divisors (7993).

15319991 is an equidigital number, since it uses as much as digits as its factorization.

15319991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7992.

The product of its digits is 10935, while the sum is 38.

The square root of 15319991 is about 3914.0760084597. The cubic root of 15319991 is about 248.3625842257.

The spelling of 15319991 in words is "fifteen million, three hundred nineteen thousand, nine hundred ninety-one".