15081991 has 4 divisors (see below), whose sum is σ = 15875800. Its totient is φ = 14288184.

The previous prime is 15081961. The next prime is 15082049. The reversal of 15081991 is 19918051.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19918051 = 3079 ⋅6469.

It is a cyclic number.

It is not a de Polignac number, because 15081991 - 2¹¹ = 15079943 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 (15081961) 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, 396876 + ... + 396913.

It is an arithmetic number, because the mean of its divisors is an integer number (3968950).

Almost surely, 2^15081991 is an apocalyptic number.

15081991 is a deficient number, since it is larger than the sum of its proper divisors (793809).

15081991 is an equidigital number, since it uses as much as digits as its factorization.

15081991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 793808.

The product of its (nonzero) digits is 3240, while the sum is 34.

The square root of 15081991 is about 3883.5539136209. The cubic root of 15081991 is about 247.0697405062.

The spelling of 15081991 in words is "fifteen million, eighty-one thousand, nine hundred ninety-one".