15987897 has 6 divisors (see below), whose sum is σ = 23093642. Its totient is φ = 10658592.

The previous prime is 15987893. The next prime is 15987901. The reversal of 15987897 is 79878951.

It is an interprime number because it is at equal distance from previous prime (15987893) and next prime (15987901).

It can be written as a sum of positive squares in only one way, i.e., 15968016 + 19881 = 3996^2 + 141^2 .

It is not a de Polignac number, because 15987897 - 2² = 15987893 is a prime.

It is a super-2 number, since 2×15987897² = 511225700965218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15987893) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 888208 + ... + 888225.

Almost surely, 2^15987897 is an apocalyptic number.

It is an amenable number.

15987897 is a deficient number, since it is larger than the sum of its proper divisors (7105745).

15987897 is a wasteful number, since it uses less digits than its factorization.

15987897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1776439 (or 1776436 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 54.

The square root of 15987897 is about 3998.4868387929. The cubic root of 15987897 is about 251.9206571831.

The spelling of 15987897 in words is "fifteen million, nine hundred eighty-seven thousand, eight hundred ninety-seven".