21121210212120 has 96 divisors (see below), whose sum is σ = 68760874138320. Its totient is φ = 5622727568640.

The previous prime is 21121210212097. The next prime is 21121210212161. The reversal of 21121210212120 is 2121201212112.

21121210212120 is a `hidden beast` number, since 2 + 1 + 121 + 210 + 212 + 120 = 666.

It is a super-2 number, since 2×21121210212120² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21121210212093 and 21121210212102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49763151 + ... + 50185790.

Almost surely, 2^{21121210212120} is an apocalyptic number.

21121210212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121210212120 is an abundant number, since it is smaller than the sum of its proper divisors (47639663926200).

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

21121210212120 is a wasteful number, since it uses less digits than its factorization.

21121210212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99949545 (or 99949538 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21121210212120 its reverse (2121201212112), we get a palindrome (23242411424232).

The spelling of 21121210212120 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred ten million, two hundred twelve thousand, one hundred twenty".