21121232100 has 36 divisors (see below), whose sum is σ = 61110765744. Its totient is φ = 5632328480.

The previous prime is 21121232053. The next prime is 21121232113. The reversal of 21121232100 is 123212112.

It is a super-2 number, since 2×21121232100² (a number of 21 digits) contains 22 as substring.

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 21121232100.

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 11 ways as a sum of consecutive naturals, for example, 35201754 + ... + 35202353.

Almost surely, 2^21121232100 is an apocalyptic number.

21121232100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121232100 is an abundant number, since it is smaller than the sum of its proper divisors (39989533644).

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

21121232100 is a wasteful number, since it uses less digits than its factorization.

21121232100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70404124 (or 70404117 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21121232100 its reverse (123212112), we get a palindrome (21244444212).

It can be divided in two parts, 21 and 121232100, that added together give a palindrome (121232121).

The spelling of 21121232100 in words is "twenty-one billion, one hundred twenty-one million, two hundred thirty-two thousand, one hundred".