21863888 has 10 divisors (see below), whose sum is σ = 42361314. Its totient is φ = 10931936.

The previous prime is 21863879. The next prime is 21863893. The reversal of 21863888 is 88836812.

It can be written as a sum of positive squares in only one way, i.e., 21641104 + 222784 = 4652^2 + 472^2 .

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 as a sum of consecutive naturals, namely, 683231 + ... + 683262.

Almost surely, 2^21863888 is an apocalyptic number.

It is an amenable number.

21863888 is a deficient number, since it is larger than the sum of its proper divisors (20497426).

21863888 is a wasteful number, since it uses less digits than its factorization.

21863888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366501 (or 1366495 counting only the distinct ones).

The product of its digits is 147456, while the sum is 44.

The square root of 21863888 is about 4675.8836598016. The cubic root of 21863888 is about 279.6248717985.

The spelling of 21863888 in words is "twenty-one million, eight hundred sixty-three thousand, eight hundred eighty-eight".