21939710 has 32 divisors (see below), whose sum is σ = 43146432. Its totient is φ = 7983360.

The previous prime is 21939703. The next prime is 21939713. The reversal of 21939710 is 1793912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8042 + ... + 10418.

It is an arithmetic number, because the mean of its divisors is an integer number (1348326).

Almost surely, 2^21939710 is an apocalyptic number.

21939710 is a deficient number, since it is larger than the sum of its proper divisors (21206722).

21939710 is a wasteful number, since it uses less digits than its factorization.

21939710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2468.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21939710 is about 4683.9844150040. The cubic root of 21939710 is about 279.9477368441.

The spelling of 21939710 in words is "twenty-one million, nine hundred thirty-nine thousand, seven hundred ten".