21438800 has 30 divisors (see below), whose sum is σ = 51507678. Its totient is φ = 8575360.

The previous prime is 21438793. The next prime is 21438827. The reversal of 21438800 is 883412.

It can be written as a sum of positive squares in 3 ways, for example, as 4857616 + 16581184 = 2204^2 + 4072^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21438800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26399 + ... + 27198.

Almost surely, 2^21438800 is an apocalyptic number.

21438800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21438800 is an abundant number, since it is smaller than the sum of its proper divisors (30068878).

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

21438800 is a wasteful number, since it uses less digits than its factorization.

21438800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53615 (or 53604 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21438800 is about 4630.2051790390. The cubic root of 21438800 is about 277.8007992772.

The spelling of 21438800 in words is "twenty-one million, four hundred thirty-eight thousand, eight hundred".