21827764 has 12 divisors (see below), whose sum is σ = 43655584. Its totient is φ = 9354744.

The previous prime is 21827753. The next prime is 21827777. The reversal of 21827764 is 46772812.

21827764 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 389754 + ... + 389809.

Almost surely, 2^21827764 is an apocalyptic number.

It is an amenable number.

21827764 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21827764 is a wasteful number, since it uses less digits than its factorization.

21827764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779574 (or 779572 counting only the distinct ones).

The product of its digits is 37632, while the sum is 37.

The square root of 21827764 is about 4672.0192636589. The cubic root of 21827764 is about 279.4707861039.

The spelling of 21827764 in words is "twenty-one million, eight hundred twenty-seven thousand, seven hundred sixty-four".