21231973800 has 96 divisors (see below), whose sum is σ = 73132372800. Its totient is φ = 5661858240.

The previous prime is 21231973793. The next prime is 21231973801. The reversal of 21231973800 is 837913212.

It is a super-2 number, since 2×21231973800² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21231973801) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1960524 + ... + 1971323.

It is an arithmetic number, because the mean of its divisors is an integer number (761795550).

Almost surely, 2^21231973800 is an apocalyptic number.

21231973800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231973800 is an abundant number, since it is smaller than the sum of its proper divisors (51900399000).

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

21231973800 is a wasteful number, since it uses less digits than its factorization.

21231973800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3931872 (or 3931857 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The spelling of 21231973800 in words is "twenty-one billion, two hundred thirty-one million, nine hundred seventy-three thousand, eight hundred".