21372265 has 16 divisors (see below), whose sum is σ = 26426880. Its totient is φ = 16585920.

The previous prime is 21372233. The next prime is 21372269. The reversal of 21372265 is 56227312.

It is not a de Polignac number, because 21372265 - 2⁵ = 21372233 is a prime.

It is a super-2 number, since 2×21372265² = 913547422460450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21372269) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23652 + ... + 24538.

It is an arithmetic number, because the mean of its divisors is an integer number (1651680).

Almost surely, 2^21372265 is an apocalyptic number.

It is an amenable number.

21372265 is a deficient number, since it is larger than the sum of its proper divisors (5054615).

21372265 is an equidigital number, since it uses as much as digits as its factorization.

21372265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1032.

The product of its digits is 5040, while the sum is 28.

The square root of 21372265 is about 4623.0147090400. The cubic root of 21372265 is about 277.5131179038.

Adding to 21372265 its reverse (56227312), we get a palindrome (77599577).

The spelling of 21372265 in words is "twenty-one million, three hundred seventy-two thousand, two hundred sixty-five".