21556434 has 16 divisors (see below), whose sum is σ = 43517088. Its totient is φ = 7118112.

The previous prime is 21556429. The next prime is 21556441. The reversal of 21556434 is 43465512.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16147 + ... + 17430.

It is an arithmetic number, because the mean of its divisors is an integer number (2719818).

Almost surely, 2^21556434 is an apocalyptic number.

21556434 is an abundant number, since it is smaller than the sum of its proper divisors (21960654).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21556434 is a wasteful number, since it uses less digits than its factorization.

21556434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33689.

The product of its digits is 14400, while the sum is 30.

The square root of 21556434 is about 4642.8906943843. The cubic root of 21556434 is about 278.3079674574.

The spelling of 21556434 in words is "twenty-one million, five hundred fifty-six thousand, four hundred thirty-four".