21522764 has 6 divisors (see below), whose sum is σ = 37664844. Its totient is φ = 10761380.

The previous prime is 21522749. The next prime is 21522791. The reversal of 21522764 is 46722512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690342 + ... + 2690349.

It is an arithmetic number, because the mean of its divisors is an integer number (6277474).

Almost surely, 2^21522764 is an apocalyptic number.

It is an amenable number.

21522764 is a deficient number, since it is larger than the sum of its proper divisors (16142080).

21522764 is a wasteful number, since it uses less digits than its factorization.

21522764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380695 (or 5380693 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21522764 is about 4639.2633035860. The cubic root of 21522764 is about 278.1629912164.

The spelling of 21522764 in words is "twenty-one million, five hundred twenty-two thousand, seven hundred sixty-four".