21002120012 has 12 divisors (see below), whose sum is σ = 36757491456. Its totient is φ = 10499979600.

The previous prime is 21002119987. The next prime is 21002120081.

It is a happy number.

21002120012 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 21002119975 and 21002120002.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225548 + ... + 304755.

It is an arithmetic number, because the mean of its divisors is an integer number (3063124288).

Almost surely, 2^21002120012 is an apocalyptic number.

It is an amenable number.

21002120012 is a deficient number, since it is larger than the sum of its proper divisors (15755371444).

21002120012 is a wasteful number, since it uses less digits than its factorization.

21002120012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540208 (or 540206 counting only the distinct ones).

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

Multiplying 21002120012 by its sum of digits (11), we get a palindrome (231023320132).

The spelling of 21002120012 in words is "twenty-one billion, two million, one hundred twenty thousand, twelve".