21265923 has 8 divisors (see below), whose sum is σ = 32405248. Its totient is φ = 12151944.

The previous prime is 21265913. The next prime is 21265943. The reversal of 21265923 is 32956212.

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

It is not a de Polignac number, because 21265923 - 2⁵ = 21265891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21265913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 506311 + ... + 506352.

It is an arithmetic number, because the mean of its divisors is an integer number (4050656).

Almost surely, 2^21265923 is an apocalyptic number.

21265923 is a deficient number, since it is larger than the sum of its proper divisors (11139325).

21265923 is a wasteful number, since it uses less digits than its factorization.

21265923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012673.

The product of its digits is 6480, while the sum is 30.

The square root of 21265923 is about 4611.4989970724. The cubic root of 21265923 is about 277.0520782931.

The spelling of 21265923 in words is "twenty-one million, two hundred sixty-five thousand, nine hundred twenty-three".