21330388 has 48 divisors (see below), whose sum is σ = 41126400. Its totient is φ = 9646560.

The previous prime is 21330383. The next prime is 21330391. The reversal of 21330388 is 88303312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21330383) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 300393 + ... + 300463.

It is an arithmetic number, because the mean of its divisors is an integer number (856800).

Almost surely, 2^21330388 is an apocalyptic number.

It is an amenable number.

21330388 is a deficient number, since it is larger than the sum of its proper divisors (19796012).

21330388 is a wasteful number, since it uses less digits than its factorization.

21330388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21330388 is about 4618.4833008251. The cubic root of 21330388 is about 277.3317455274.

The spelling of 21330388 in words is "twenty-one million, three hundred thirty thousand, three hundred eighty-eight".