21265237 has 16 divisors (see below), whose sum is σ = 25718400. Its totient is φ = 17176320.

The previous prime is 21265219. The next prime is 21265241. The reversal of 21265237 is 73256212.

It is not a de Polignac number, because 21265237 - 2¹⁵ = 21232469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21265217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37089 + ... + 37657.

It is an arithmetic number, because the mean of its divisors is an integer number (1607400).

Almost surely, 2^21265237 is an apocalyptic number.

It is an amenable number.

21265237 is a deficient number, since it is larger than the sum of its proper divisors (4453163).

21265237 is a wasteful number, since it uses less digits than its factorization.

21265237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 876.

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

The square root of 21265237 is about 4611.4246171872. The cubic root of 21265237 is about 277.0490991957.

The spelling of 21265237 in words is "twenty-one million, two hundred sixty-five thousand, two hundred thirty-seven".