21012120210021 has 8 divisors (see below), whose sum is σ = 28033993615584. Its totient is φ = 13999163472240.

The previous prime is 21012120210001. The next prime is 21012120210113. The reversal of 21012120210021 is 12001202121012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21012120210021 - 2⁶ = 21012120209957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012120210001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2229161446 + ... + 2229170871.

It is an arithmetic number, because the mean of its divisors is an integer number (3504249201948).

Almost surely, 2^{21012120210021} is an apocalyptic number.

It is an amenable number.

21012120210021 is a deficient number, since it is larger than the sum of its proper divisors (7021873405563).

21012120210021 is a wasteful number, since it uses less digits than its factorization.

21012120210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4458333891.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21012120210021 its reverse (12001202121012), we get a palindrome (33013322331033).

The spelling of 21012120210021 in words is "twenty-one trillion, twelve billion, one hundred twenty million, two hundred ten thousand, twenty-one".