21001012012120 has 96 divisors (see below), whose sum is σ = 54970661389680. Its totient is φ = 7199858776320.

The previous prime is 21001012012063. The next prime is 21001012012157. The reversal of 21001012012120 is 2121021010012.

It is a self number, because there is not a number n which added to its sum of digits gives 21001012012120.

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, 29163847 + ... + 29875273.

Almost surely, 2^{21001012012120} is an apocalyptic number.

21001012012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001012012120 is an abundant number, since it is smaller than the sum of its proper divisors (33969649377560).

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

21001012012120 is a wasteful number, since it uses less digits than its factorization.

21001012012120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726513 (or 726502 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21001012012120 its reverse (2121021010012), we get a palindrome (23122033022132).

The spelling of 21001012012120 in words is "twenty-one trillion, one billion, twelve million, twelve thousand, one hundred twenty".