21131331100 has 108 divisors (see below), whose sum is σ = 50904570024. Its totient is φ = 7607600000.

The previous prime is 21131331077. The next prime is 21131331113. The reversal of 21131331100 is 113313112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1213455 + ... + 1230745.

Almost surely, 2^21131331100 is an apocalyptic number.

21131331100 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 21131331100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25452285012).

21131331100 is an abundant number, since it is smaller than the sum of its proper divisors (29773238924).

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

21131331100 is a wasteful number, since it uses less digits than its factorization.

21131331100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17428 (or 17410 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

Adding to 21131331100 its reverse (113313112), we get a palindrome (21244644212).

The spelling of 21131331100 in words is "twenty-one billion, one hundred thirty-one million, three hundred thirty-one thousand, one hundred".