21275023 has 32 divisors (see below), whose sum is σ = 28449792. Its totient is φ = 15417600.

The previous prime is 21275017. The next prime is 21275027. The reversal of 21275023 is 32057212.

It is not a de Polignac number, because 21275023 - 2⁵ = 21274991 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21274985 and 21275003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275027) 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 31 ways as a sum of consecutive naturals, for example, 72465 + ... + 72757.

It is an arithmetic number, because the mean of its divisors is an integer number (889056).

Almost surely, 2^21275023 is an apocalyptic number.

21275023 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21275023 is a deficient number, since it is larger than the sum of its proper divisors (7174769).

21275023 is a wasteful number, since it uses less digits than its factorization.

21275023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21275023 is about 4612.4855555329. The cubic root of 21275023 is about 277.0915908721.

The spelling of 21275023 in words is "twenty-one million, two hundred seventy-five thousand, twenty-three".