21012121122120 has 96 divisors (see below), whose sum is σ = 68333368030200. Its totient is φ = 5599624144896.

The previous prime is 21012121122101. The next prime is 21012121122217. The reversal of 21012121122120 is 2122112121012.

21012121122120 is a `hidden beast` number, since 210 + 1 + 2 + 1 + 211 + 221 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 11781960140196 + 9230160981924 = 3432486^2 + 3038118^2 .

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 = 21012121122093 and 21012121122102.

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, 18232615 + ... + 19350774.

Almost surely, 2^{21012121122120} is an apocalyptic number.

21012121122120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012121122120 is an abundant number, since it is smaller than the sum of its proper divisors (47321246908080).

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

21012121122120 is a wasteful number, since it uses less digits than its factorization.

21012121122120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37584959 (or 37584952 counting only the distinct ones).

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

Adding to 21012121122120 its reverse (2122112121012), we get a palindrome (23134233243132).

The spelling of 21012121122120 in words is "twenty-one trillion, twelve billion, one hundred twenty-one million, one hundred twenty-two thousand, one hundred twenty".