21379388 has 6 divisors (see below), whose sum is σ = 37413936. Its totient is φ = 10689692.

The previous prime is 21379363. The next prime is 21379399. The reversal of 21379388 is 88397312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2672420 + ... + 2672427.

It is an arithmetic number, because the mean of its divisors is an integer number (6235656).

Almost surely, 2^21379388 is an apocalyptic number.

It is an amenable number.

21379388 is a deficient number, since it is larger than the sum of its proper divisors (16034548).

21379388 is a wasteful number, since it uses less digits than its factorization.

21379388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5344851 (or 5344849 counting only the distinct ones).

The product of its digits is 72576, while the sum is 41.

The square root of 21379388 is about 4623.7850296051. The cubic root of 21379388 is about 277.5439445597.

The spelling of 21379388 in words is "twenty-one million, three hundred seventy-nine thousand, three hundred eighty-eight".