21120123100 has 36 divisors (see below), whose sum is σ = 45837064504. Its totient is φ = 8446870080.

The previous prime is 21120123067. The next prime is 21120123109. The reversal of 21120123100 is 132102112.

It is a super-2 number, since 2×21120123100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120123109) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1219099 + ... + 1236301.

Almost surely, 2^21120123100 is an apocalyptic number.

21120123100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120123100 is an abundant number, since it is smaller than the sum of its proper divisors (24716941404).

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

21120123100 is a wasteful number, since it uses less digits than its factorization.

21120123100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29494 (or 29487 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21120123100 its reverse (132102112), we get a palindrome (21252225212).

It can be divided in two parts, 2112012 and 3100, that added together give a palindrome (2115112).

The spelling of 21120123100 in words is "twenty-one billion, one hundred twenty million, one hundred twenty-three thousand, one hundred".