21002105312 has 24 divisors (see below), whose sum is σ = 42773686200. Its totient is φ = 10138946944.

The previous prime is 21002105309. The next prime is 21002105321. The reversal of 21002105312 is 21350120012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11314862 + ... + 11316717.

It is an arithmetic number, because the mean of its divisors is an integer number (1782236925).

Almost surely, 2^21002105312 is an apocalyptic number.

It is an amenable number.

21002105312 is an abundant number, since it is smaller than the sum of its proper divisors (21771580888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21002105312 is a wasteful number, since it uses less digits than its factorization.

21002105312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22631618 (or 22631610 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

Adding to 21002105312 its reverse (21350120012), we get a palindrome (42352225324).

The spelling of 21002105312 in words is "twenty-one billion, two million, one hundred five thousand, three hundred twelve".