21813400 has 48 divisors (see below), whose sum is σ = 57965040. Its totient is φ = 7478400.

The previous prime is 21813383. The next prime is 21813403. The reversal of 21813400 is 431812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813403) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 6391 + ... + 9190.

It is an arithmetic number, because the mean of its divisors is an integer number (1207605).

Almost surely, 2^21813400 is an apocalyptic number.

21813400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21813400 is an abundant number, since it is smaller than the sum of its proper divisors (36151640).

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

21813400 is a wasteful number, since it uses less digits than its factorization.

21813400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15604 (or 15595 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21813400 is about 4670.4817738644. The cubic root of 21813400 is about 279.4094697112.

The spelling of 21813400 in words is "twenty-one million, eight hundred thirteen thousand, four hundred".