21012002121021 has 16 divisors (see below), whose sum is σ = 28101601382400. Its totient is φ = 13965223137008.

The previous prime is 21012002121017. The next prime is 21012002121041. The reversal of 21012002121021 is 12012120021012.

It is a cyclic number.

It is not a de Polignac number, because 21012002121021 - 2² = 21012002121017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012002121041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1382380 + ... + 6628346.

It is an arithmetic number, because the mean of its divisors is an integer number (1756350086400).

Almost surely, 2^{21012002121021} is an apocalyptic number.

It is an amenable number.

21012002121021 is a deficient number, since it is larger than the sum of its proper divisors (7089599261379).

21012002121021 is a wasteful number, since it uses less digits than its factorization.

21012002121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5250048.

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

Adding to 21012002121021 its reverse (12012120021012), we get a palindrome (33024122142033).

The spelling of 21012002121021 in words is "twenty-one trillion, twelve billion, two million, one hundred twenty-one thousand, twenty-one".