21458040 has 32 divisors (see below), whose sum is σ = 64374480. Its totient is φ = 5722112.

The previous prime is 21458033. The next prime is 21458069. The reversal of 21458040 is 4085412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21458040.

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 in 7 ways as a sum of consecutive naturals, for example, 89289 + ... + 89528.

Almost surely, 2^21458040 is an apocalyptic number.

21458040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21458040 is an abundant number, since it is smaller than the sum of its proper divisors (42916440).

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

21458040 is a wasteful number, since it uses less digits than its factorization.

21458040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178831 (or 178827 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21458040 is about 4632.2823748127. The cubic root of 21458040 is about 277.8838774543.

The spelling of 21458040 in words is "twenty-one million, four hundred fifty-eight thousand, forty".