21648964 has 12 divisors (see below), whose sum is σ = 39192300. Its totient is φ = 10451168.

The previous prime is 21648947. The next prime is 21648997. The reversal of 21648964 is 46984612.

It can be written as a sum of positive squares in 2 ways, for example, as 7884864 + 13764100 = 2808^2 + 3710^2 .

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, 93199 + ... + 93430.

It is an arithmetic number, because the mean of its divisors is an integer number (3266025).

Almost surely, 2^21648964 is an apocalyptic number.

It is an amenable number.

21648964 is a deficient number, since it is larger than the sum of its proper divisors (17543336).

21648964 is a wasteful number, since it uses less digits than its factorization.

21648964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186662 (or 186660 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 21648964 is about 4652.8447212431. The cubic root of 21648964 is about 278.7056070926.

The spelling of 21648964 in words is "twenty-one million, six hundred forty-eight thousand, nine hundred sixty-four".