21983764 has 36 divisors (see below), whose sum is σ = 43135092. Its totient is φ = 9792640.

The previous prime is 21983747. The next prime is 21983807. The reversal of 21983764 is 46738912.

It can be written as a sum of positive squares in 2 ways, for example, as 18404100 + 3579664 = 4290^2 + 1892^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25224 + ... + 26080.

It is an arithmetic number, because the mean of its divisors is an integer number (1198197).

Almost surely, 2^21983764 is an apocalyptic number.

It is an amenable number.

21983764 is a deficient number, since it is larger than the sum of its proper divisors (21151328).

21983764 is a wasteful number, since it uses less digits than its factorization.

21983764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936 (or 923 counting only the distinct ones).

The product of its digits is 72576, while the sum is 40.

The square root of 21983764 is about 4688.6846769643. The cubic root of 21983764 is about 280.1349859342.

The spelling of 21983764 in words is "twenty-one million, nine hundred eighty-three thousand, seven hundred sixty-four".