21930638 has 8 divisors (see below), whose sum is σ = 34326288. Its totient is φ = 10488544.

The previous prime is 21930619. The next prime is 21930647. The reversal of 21930638 is 83603912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238331 + ... + 238422.

It is an arithmetic number, because the mean of its divisors is an integer number (4290786).

Almost surely, 2^21930638 is an apocalyptic number.

21930638 is a deficient number, since it is larger than the sum of its proper divisors (12395650).

21930638 is a wasteful number, since it uses less digits than its factorization.

21930638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476778.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21930638 is about 4683.0159085786. The cubic root of 21930638 is about 279.9091456929.

The spelling of 21930638 in words is "twenty-one million, nine hundred thirty thousand, six hundred thirty-eight".