21774664 has 16 divisors (see below), whose sum is σ = 40938300. Its totient is φ = 10857792.

The previous prime is 21774647. The next prime is 21774667. The reversal of 21774664 is 46647712.

It can be written as a sum of positive squares in 2 ways, for example, as 20629764 + 1144900 = 4542^2 + 1070^2 .

It is not an unprimeable number, because it can be changed into a prime (21774667) 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, 387 + ... + 6610.

Almost surely, 2^21774664 is an apocalyptic number.

It is an amenable number.

21774664 is a deficient number, since it is larger than the sum of its proper divisors (19163636).

21774664 is a wasteful number, since it uses less digits than its factorization.

21774664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7392 (or 7388 counting only the distinct ones).

The product of its digits is 56448, while the sum is 37.

The square root of 21774664 is about 4666.3330356930. Note that the first 3 decimals coincide. The cubic root of 21774664 is about 279.2439809425.

The spelling of 21774664 in words is "twenty-one million, seven hundred seventy-four thousand, six hundred sixty-four".