21131231100 has 72 divisors (see below), whose sum is σ = 69873944448. Its totient is φ = 4829995200.

The previous prime is 21131231021. The next prime is 21131231101. The reversal of 21131231100 is 113213112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21131231100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131231101) 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, 5029146 + ... + 5033345.

Almost surely, 2^21131231100 is an apocalyptic number.

21131231100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131231100 is an abundant number, since it is smaller than the sum of its proper divisors (48742713348).

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

21131231100 is a wasteful number, since it uses less digits than its factorization.

21131231100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10062515 (or 10062508 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21131231100 its reverse (113213112), we get a palindrome (21244444212).

The spelling of 21131231100 in words is "twenty-one billion, one hundred thirty-one million, two hundred thirty-one thousand, one hundred".