21002121002 has 16 divisors (see below), whose sum is σ = 32105593512. Its totient is φ = 10300355520.

The previous prime is 21002120999. The next prime is 21002121013. The reversal of 21002121002 is 20012120012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20964433681 + 37687321 = 144791^2 + 6139^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 443552 + ... + 488612.

Almost surely, 2^21002121002 is an apocalyptic number.

21002121002 is a deficient number, since it is larger than the sum of its proper divisors (11103472510).

21002121002 is a wasteful number, since it uses less digits than its factorization.

21002121002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49513.

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

Adding to 21002121002 its reverse (20012120012), we get a palindrome (41014241014).

The spelling of 21002121002 in words is "twenty-one billion, two million, one hundred twenty-one thousand, two".