21388484 has 24 divisors (see below), whose sum is σ = 40446168. Its totient is φ = 9838080.

The previous prime is 21388469. The next prime is 21388517. The reversal of 21388484 is 48488312.

It can be written as a sum of positive squares in 4 ways, for example, as 228484 + 21160000 = 478^2 + 4600^2 .

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

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 in 7 ways as a sum of consecutive naturals, for example, 21404 + ... + 22380.

It is an arithmetic number, because the mean of its divisors is an integer number (1685257).

Almost surely, 2^21388484 is an apocalyptic number.

It is an amenable number.

21388484 is a deficient number, since it is larger than the sum of its proper divisors (19057684).

21388484 is a wasteful number, since it uses less digits than its factorization.

21388484 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1415 (or 1413 counting only the distinct ones).

The product of its digits is 49152, while the sum is 38.

The square root of 21388484 is about 4624.7685347485. The cubic root of 21388484 is about 277.5832999391.

The spelling of 21388484 in words is "twenty-one million, three hundred eighty-eight thousand, four hundred eighty-four".