21002120121005 has 8 divisors (see below), whose sum is σ = 26298306934272. Its totient is φ = 16071187570768.

The previous prime is 21002120120951. The next prime is 21002120121007. The reversal of 21002120121005 is 50012102120012.

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

It is a cyclic number.

It is not a de Polignac number, because 21002120121005 - 2⁸ = 21002120120749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002120121007) 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, 91313565629 + ... + 91313565858.

It is an arithmetic number, because the mean of its divisors is an integer number (3287288366784).

Almost surely, 2^{21002120121005} is an apocalyptic number.

It is an amenable number.

21002120121005 is a deficient number, since it is larger than the sum of its proper divisors (5296186813267).

21002120121005 is a wasteful number, since it uses less digits than its factorization.

21002120121005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182627131515.

The product of its (nonzero) digits is 80, while the sum is 17.

Adding to 21002120121005 its reverse (50012102120012), we get a palindrome (71014222241017).

The spelling of 21002120121005 in words is "twenty-one trillion, two billion, one hundred twenty million, one hundred twenty-one thousand, five".