21739128 has 32 divisors (see below), whose sum is σ = 55818960. Its totient is φ = 7050240.

The previous prime is 21739103. The next prime is 21739129. The reversal of 21739128 is 82193712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11353 + ... + 13128.

Almost surely, 2^21739128 is an apocalyptic number.

It is an amenable number.

21739128 is an abundant number, since it is smaller than the sum of its proper divisors (34079832).

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

21739128 is a wasteful number, since it uses less digits than its factorization.

21739128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24527 (or 24523 counting only the distinct ones).

The product of its digits is 6048, while the sum is 33.

The square root of 21739128 is about 4662.5237801002. The cubic root of 21739128 is about 279.0919905804.

The spelling of 21739128 in words is "twenty-one million, seven hundred thirty-nine thousand, one hundred twenty-eight".