21124900 has 36 divisors (see below), whose sum is σ = 46177600. Its totient is φ = 8388000.

The previous prime is 21124877. The next prime is 21124927. The reversal of 21124900 is 942112.

It is a super-2 number, since 2×21124900² = 892522800020000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14401 + ... + 15799.

Almost surely, 2^21124900 is an apocalyptic number.

21124900 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 21124900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23088800).

21124900 is an abundant number, since it is smaller than the sum of its proper divisors (25052700).

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

21124900 is a wasteful number, since it uses less digits than its factorization.

21124900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1564 (or 1557 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21124900 is about 4596.1831991338. The cubic root of 21124900 is about 276.4383044880.

The spelling of 21124900 in words is "twenty-one million, one hundred twenty-four thousand, nine hundred".