21253956 has 24 divisors (see below), whose sum is σ = 49929600. Its totient is φ = 7036512.

The previous prime is 21253943. The next prime is 21253957. The reversal of 21253956 is 65935212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253957) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4156 + ... + 7731.

It is an arithmetic number, because the mean of its divisors is an integer number (2080400).

Almost surely, 2^21253956 is an apocalyptic number.

It is an amenable number.

21253956 is an abundant number, since it is smaller than the sum of its proper divisors (28675644).

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

21253956 is a wasteful number, since it uses less digits than its factorization.

21253956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12043 (or 12041 counting only the distinct ones).

The product of its digits is 16200, while the sum is 33.

The square root of 21253956 is about 4610.2012971236. The cubic root of 21253956 is about 277.0000999187. Note that the first 4 decimals are identical.

The spelling of 21253956 in words is "twenty-one million, two hundred fifty-three thousand, nine hundred fifty-six".