21292556 has 6 divisors (see below), whose sum is σ = 37261980. Its totient is φ = 10646276.

The previous prime is 21292553. The next prime is 21292561. The reversal of 21292556 is 65529212.

It is not an unprimeable number, because it can be changed into a prime (21292553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2661566 + ... + 2661573.

It is an arithmetic number, because the mean of its divisors is an integer number (6210330).

Almost surely, 2^21292556 is an apocalyptic number.

It is an amenable number.

21292556 is a deficient number, since it is larger than the sum of its proper divisors (15969424).

21292556 is a wasteful number, since it uses less digits than its factorization.

21292556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5323143 (or 5323141 counting only the distinct ones).

The product of its digits is 10800, while the sum is 32.

The square root of 21292556 is about 4614.3857662749. The cubic root of 21292556 is about 277.1676881324.

The spelling of 21292556 in words is "twenty-one million, two hundred ninety-two thousand, five hundred fifty-six".