15879921 has 8 divisors (see below), whose sum is σ = 22418784. Its totient is φ = 9963840.

The previous prime is 15879917. The next prime is 15880009. The reversal of 15879921 is 12997851.

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

It is not a de Polignac number, because 15879921 - 2² = 15879917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15879911) 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, 155635 + ... + 155736.

It is an arithmetic number, because the mean of its divisors is an integer number (2802348).

Almost surely, 2^15879921 is an apocalyptic number.

It is an amenable number.

15879921 is a deficient number, since it is larger than the sum of its proper divisors (6538863).

15879921 is a wasteful number, since it uses less digits than its factorization.

15879921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311391.

The product of its digits is 45360, while the sum is 42.

The square root of 15879921 is about 3984.9618567811. The cubic root of 15879921 is about 251.3522511463.

The spelling of 15879921 in words is "fifteen million, eight hundred seventy-nine thousand, nine hundred twenty-one".