21420912 has 40 divisors (see below), whose sum is σ = 57746304. Its totient is φ = 6829504.

The previous prime is 21420887. The next prime is 21420941. The reversal of 21420912 is 21902412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8598 + ... + 10805.

Almost surely, 2^21420912 is an apocalyptic number.

It is an amenable number.

21420912 is an abundant number, since it is smaller than the sum of its proper divisors (36325392).

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

21420912 is a wasteful number, since it uses less digits than its factorization.

21420912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19437 (or 19431 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21420912 is about 4628.2731120797. The cubic root of 21420912 is about 277.7235144256.

The spelling of 21420912 in words is "twenty-one million, four hundred twenty thousand, nine hundred twelve".