21372915 has 16 divisors (see below), whose sum is σ = 34610688. Its totient is φ = 11260896.

The previous prime is 21372889. The next prime is 21372937. The reversal of 21372915 is 51927312.

It is not a de Polignac number, because 21372915 - 2⁷ = 21372787 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7339 + ... + 9828.

It is an arithmetic number, because the mean of its divisors is an integer number (2163168).

Almost surely, 2^21372915 is an apocalyptic number.

21372915 is a deficient number, since it is larger than the sum of its proper divisors (13237773).

21372915 is a wasteful number, since it uses less digits than its factorization.

21372915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17258.

The product of its digits is 3780, while the sum is 30.

The square root of 21372915 is about 4623.0850089524. The cubic root of 21372915 is about 277.5159312337.

The spelling of 21372915 in words is "twenty-one million, three hundred seventy-two thousand, nine hundred fifteen".