21002120121001 has 8 divisors (see below), whose sum is σ = 21013571581184. Its totient is φ = 20990671756560.

The previous prime is 21002120120951. The next prime is 21002120121007. The reversal of 21002120121001 is 10012102120012.

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 21002120121001 - 2⁷ = 21002120120873 is a prime.

It is a Duffinian 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, 12863560 + ... + 14404006.

It is an arithmetic number, because the mean of its divisors is an integer number (2626696447648).

Almost surely, 2^{21002120121001} is an apocalyptic number.

It is an amenable number.

21002120121001 is a deficient number, since it is larger than the sum of its proper divisors (11451460183).

21002120121001 is a wasteful number, since it uses less digits than its factorization.

21002120121001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1547871.

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

Adding to 21002120121001 its reverse (10012102120012), we get a palindrome (31014222241013).

The spelling of 21002120121001 in words is "twenty-one trillion, two billion, one hundred twenty million, one hundred twenty-one thousand, one".