21532623 has 32 divisors (see below), whose sum is σ = 34636800. Its totient is φ = 11632896.

The previous prime is 21532619. The next prime is 21532633. The reversal of 21532623 is 32623512.

It is not a de Polignac number, because 21532623 - 2² = 21532619 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21532593 and 21532602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21532603) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52443 + ... + 52851.

It is an arithmetic number, because the mean of its divisors is an integer number (1082400).

Almost surely, 2^21532623 is an apocalyptic number.

21532623 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21532623 is a deficient number, since it is larger than the sum of its proper divisors (13104177).

21532623 is a wasteful number, since it uses less digits than its factorization.

21532623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551.

The product of its digits is 2160, while the sum is 24.

The square root of 21532623 is about 4640.3257428762. The cubic root of 21532623 is about 278.2054577307.

It can be divided in two parts, 21532 and 623, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21532623 in words is "twenty-one million, five hundred thirty-two thousand, six hundred twenty-three".