21002120121023 has 8 divisors (see below), whose sum is σ = 21136129165200. Its totient is φ = 20868114084480.

The previous prime is 21002120121013. The next prime is 21002120121049. The reversal of 21002120121023 is 32012102120012.

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 21002120121023 - 2⁴ = 21002120121007 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002120120992 and 21002120121010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002120121013) 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, 14204528 + ... + 15613226.

It is an arithmetic number, because the mean of its divisors is an integer number (2642016145650).

Almost surely, 2^{21002120121023} is an apocalyptic number.

21002120121023 is a deficient number, since it is larger than the sum of its proper divisors (134009044177).

21002120121023 is a wasteful number, since it uses less digits than its factorization.

21002120121023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1503817.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21002120121023 its reverse (32012102120012), we get a palindrome (53014222241035).

The spelling of 21002120121023 in words is "twenty-one trillion, two billion, one hundred twenty million, one hundred twenty-one thousand, twenty-three".