15115987 has 4 divisors (see below), whose sum is σ = 15143400. Its totient is φ = 15088576.

The previous prime is 15115981. The next prime is 15116021. The reversal of 15115987 is 78951151.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78951151 = 6653 ⋅11867.

It is a cyclic number.

It is not a de Polignac number, because 15115987 - 2³ = 15115979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15115981) 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, 12862 + ... + 13987.

It is an arithmetic number, because the mean of its divisors is an integer number (3785850).

Almost surely, 2^15115987 is an apocalyptic number.

15115987 is a deficient number, since it is larger than the sum of its proper divisors (27413).

15115987 is an equidigital number, since it uses as much as digits as its factorization.

15115987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27412.

The product of its digits is 12600, while the sum is 37.

The square root of 15115987 is about 3887.9283686817. The cubic root of 15115987 is about 247.2552394418.

The spelling of 15115987 in words is "fifteen million, one hundred fifteen thousand, nine hundred eighty-seven".