21353888 has 12 divisors (see below), whose sum is σ = 42040530. Its totient is φ = 10676928.

The previous prime is 21353879. The next prime is 21353897. The reversal of 21353888 is 88835312.

It is an interprime number because it is at equal distance from previous prime (21353879) and next prime (21353897).

It can be written as a sum of positive squares in only one way, i.e., 14531344 + 6822544 = 3812^2 + 2612^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333623 + ... + 333686.

Almost surely, 2^21353888 is an apocalyptic number.

It is an amenable number.

21353888 is a deficient number, since it is larger than the sum of its proper divisors (20686642).

21353888 is an equidigital number, since it uses as much as digits as its factorization.

21353888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667319 (or 667311 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 21353888 is about 4621.0267257396. The cubic root of 21353888 is about 277.4335549597.

The spelling of 21353888 in words is "twenty-one million, three hundred fifty-three thousand, eight hundred eighty-eight".