10002120021 has 12 divisors (see below), whose sum is σ = 14580054060. Its totient is φ = 6606904320.

The previous prime is 10002119947. The next prime is 10002120031. The reversal of 10002120021 is 12002120001.

It can be written as a sum of positive squares in 2 ways, for example, as 5591300625 + 4410819396 = 74775^2 + 66414^2 .

It is not a de Polignac number, because 10002120021 - 2¹⁵ = 10002087253 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 10002119985 and 10002120012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10002120031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5096940 + ... + 5098901.

It is an arithmetic number, because the mean of its divisors is an integer number (1215004505).

Almost surely, 2^10002120021 is an apocalyptic number.

It is an amenable number.

10002120021 is a deficient number, since it is larger than the sum of its proper divisors (4577934039).

10002120021 is a wasteful number, since it uses less digits than its factorization.

10002120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10195956 (or 10195953 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 10002120021 its reverse (12002120001), we get a palindrome (22004240022).

The spelling of 10002120021 in words is "ten billion, two million, one hundred twenty thousand, twenty-one".