21368400 has 60 divisors (see below), whose sum is σ = 68453952. Its totient is φ = 5697920.

The previous prime is 21368387. The next prime is 21368401. The reversal of 21368400 is 486312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7704 + ... + 10103.

Almost surely, 2^21368400 is an apocalyptic number.

21368400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21368400 is an abundant number, since it is smaller than the sum of its proper divisors (47085552).

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

21368400 is a wasteful number, since it uses less digits than its factorization.

21368400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17828 (or 17817 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21368400 is about 4622.5966728669. The cubic root of 21368400 is about 277.4963882332.

The spelling of 21368400 in words is "twenty-one million, three hundred sixty-eight thousand, four hundred".