21380528 has 30 divisors (see below), whose sum is σ = 44862084. Its totient is φ = 9866688.

The previous prime is 21380521. The next prime is 21380539. The reversal of 21380528 is 82508312.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21380528.

It is not an unprimeable number, because it can be changed into a prime (21380521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1250 + ... + 6657.

Almost surely, 2^21380528 is an apocalyptic number.

It is an amenable number.

21380528 is an abundant number, since it is smaller than the sum of its proper divisors (23481556).

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

21380528 is a wasteful number, since it uses less digits than its factorization.

21380528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7941 (or 7922 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 21380528 is about 4623.9083035891. The cubic root of 21380528 is about 277.5488775739.

The spelling of 21380528 in words is "twenty-one million, three hundred eighty thousand, five hundred twenty-eight".