21000000012 has 48 divisors (see below), whose sum is σ = 49758922752. Its totient is φ = 6891698880.

The previous prime is 20999999981. The next prime is 21000000019.

It is a happy number.

21000000012 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is not an unprimeable number, because it can be changed into a prime (21000000019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1691058 + ... + 1703430.

It is an arithmetic number, because the mean of its divisors is an integer number (1036644224).

Almost surely, 2^21000000012 is an apocalyptic number.

It is an amenable number.

21000000012 is an abundant number, since it is smaller than the sum of its proper divisors (28758922740).

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

21000000012 is a wasteful number, since it uses less digits than its factorization.

21000000012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14558 (or 14556 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

It can be divided in two parts, 210000000 and 12, that added together give a palindrome (210000012).

The spelling of 21000000012 in words is "twenty-one billion, twelve", and thus it is an aban number and an uban number.