21057384 has 32 divisors (see below), whose sum is σ = 52920000. Its totient is φ = 6982272.

The previous prime is 21057341. The next prime is 21057419. The reversal of 21057384 is 48375012.

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, 2572 + ... + 6980.

It is an arithmetic number, because the mean of its divisors is an integer number (1653750).

Almost surely, 2^21057384 is an apocalyptic number.

21057384 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21057384 is an abundant number, since it is smaller than the sum of its proper divisors (31862616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21057384 is a wasteful number, since it uses less digits than its factorization.

21057384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4617 (or 4613 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 21057384 is about 4588.8325312654. The cubic root of 21057384 is about 276.1434876671.

The spelling of 21057384 in words is "twenty-one million, fifty-seven thousand, three hundred eighty-four".