21947910 has 16 divisors (see below), whose sum is σ = 52675056. Its totient is φ = 5852768.

The previous prime is 21947903. The next prime is 21947921. The reversal of 21947910 is 1974912.

It is a congruent 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, 365769 + ... + 365828.

It is an arithmetic number, because the mean of its divisors is an integer number (3292191).

Almost surely, 2^21947910 is an apocalyptic number.

21947910 is an abundant number, since it is smaller than the sum of its proper divisors (30727146).

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

21947910 is a wasteful number, since it uses less digits than its factorization.

21947910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731607.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 21947910 is about 4684.8596563825. The cubic root of 21947910 is about 279.9826094641.

The spelling of 21947910 in words is "twenty-one million, nine hundred forty-seven thousand, nine hundred ten".