21002200121 has 12 divisors (see below), whose sum is σ = 24434975232. Its totient is φ = 17999053128.

The previous prime is 21002200117. The next prime is 21002200123. The reversal of 21002200121 is 12100220012.

It is a happy number.

It is not a de Polignac number, because 21002200121 - 2² = 21002200117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002200123) 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, 317876 + ... + 378218.

It is an arithmetic number, because the mean of its divisors is an integer number (2036247936).

Almost surely, 2^21002200121 is an apocalyptic number.

It is an amenable number.

21002200121 is a deficient number, since it is larger than the sum of its proper divisors (3432775111).

21002200121 is an equidigital number, since it uses as much as digits as its factorization.

21002200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67460 (or 67453 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21002200121 its reverse (12100220012), we get a palindrome (33102420133).

The spelling of 21002200121 in words is "twenty-one billion, two million, two hundred thousand, one hundred twenty-one".