21775028 has 48 divisors (see below), whose sum is σ = 45105984. Its totient is φ = 9085440.

The previous prime is 21774983. The next prime is 21775031. The reversal of 21775028 is 82057712.

It is a junction number, because it is equal to n+sod(n) for n = 21774985 and 21775003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31826 + ... + 32502.

It is an arithmetic number, because the mean of its divisors is an integer number (939708).

Almost surely, 2^21775028 is an apocalyptic number.

It is an amenable number.

21775028 is an abundant number, since it is smaller than the sum of its proper divisors (23330956).

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

21775028 is a wasteful number, since it uses less digits than its factorization.

21775028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 21775028 is about 4666.3720383184. The cubic root of 21775028 is about 279.2455369442.

The spelling of 21775028 in words is "twenty-one million, seven hundred seventy-five thousand, twenty-eight".