21528768 has 28 divisors (see below), whose sum is σ = 56962040. Its totient is φ = 7176192.

The previous prime is 21528743. The next prime is 21528769. The reversal of 21528768 is 86782512.

It is not an unprimeable number, because it can be changed into a prime (21528769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55873 + ... + 56256.

Almost surely, 2^21528768 is an apocalyptic number.

It is an amenable number.

21528768 is an abundant number, since it is smaller than the sum of its proper divisors (35433272).

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

21528768 is a wasteful number, since it uses less digits than its factorization.

21528768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112144 (or 112134 counting only the distinct ones).

The product of its digits is 53760, while the sum is 39.

The square root of 21528768 is about 4639.9103439614. The cubic root of 21528768 is about 278.1888543030.

The spelling of 21528768 in words is "twenty-one million, five hundred twenty-eight thousand, seven hundred sixty-eight".