21254920 has 32 divisors (see below), whose sum is σ = 50342400. Its totient is φ = 8054208.

The previous prime is 21254903. The next prime is 21254923. The reversal of 21254920 is 2945212.

It is not an unprimeable number, because it can be changed into a prime (21254923) 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, 13224 + ... + 14743.

It is an arithmetic number, because the mean of its divisors is an integer number (1573200).

Almost surely, 2^21254920 is an apocalyptic number.

21254920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21254920 is an abundant number, since it is smaller than the sum of its proper divisors (29087480).

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

21254920 is a wasteful number, since it uses less digits than its factorization.

21254920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27997 (or 27993 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21254920 is about 4610.3058466874. The cubic root of 21254920 is about 277.0042877518.

The spelling of 21254920 in words is "twenty-one million, two hundred fifty-four thousand, nine hundred twenty".