21092400 has 360 divisors, whose sum is σ = 89549824. Its totient is φ = 4665600.

The previous prime is 21092399. The next prime is 21092411. The reversal of 21092400 is 429012.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 680385 + ... + 680415.

Almost surely, 2^21092400 is an apocalyptic number.

21092400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21092400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44774912).

21092400 is an abundant number, since it is smaller than the sum of its proper divisors (68457424).

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

21092400 is a wasteful number, since it uses less digits than its factorization.

21092400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71 (or 48 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21092400 is about 4592.6462959823. The cubic root of 21092400 is about 276.2964678219.

The spelling of 21092400 in words is "twenty-one million, ninety-two thousand, four hundred".