21011312100 has 72 divisors (see below), whose sum is σ = 62435809408. Its totient is φ = 5451580800.

The previous prime is 21011312053. The next prime is 21011312111. The reversal of 21011312100 is 121311012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 935356 + ... + 957555.

Almost surely, 2^21011312100 is an apocalyptic number.

21011312100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011312100 is an abundant number, since it is smaller than the sum of its proper divisors (41424497308).

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

21011312100 is a wasteful number, since it uses less digits than its factorization.

21011312100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1892965 (or 1892958 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 12.

Adding to 21011312100 its reverse (121311012), we get a palindrome (21132623112).

The spelling of 21011312100 in words is "twenty-one billion, eleven million, three hundred twelve thousand, one hundred".