21863764 has 12 divisors (see below), whose sum is σ = 41204884. Its totient is φ = 10090944.

The previous prime is 21863759. The next prime is 21863771. The reversal of 21863764 is 46736812.

It can be written as a sum of positive squares in 2 ways, for example, as 887364 + 20976400 = 942^2 + 4580^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 210177 + ... + 210280.

Almost surely, 2^21863764 is an apocalyptic number.

It is an amenable number.

21863764 is a deficient number, since it is larger than the sum of its proper divisors (19341120).

21863764 is a wasteful number, since it uses less digits than its factorization.

21863764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420474 (or 420472 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 21863764 is about 4675.8704002570. The cubic root of 21863764 is about 279.6243431711.

The spelling of 21863764 in words is "twenty-one million, eight hundred sixty-three thousand, seven hundred sixty-four".