21012001012 has 6 divisors (see below), whose sum is σ = 36771001778. Its totient is φ = 10506000504.

The previous prime is 21012000983. The next prime is 21012001039. The reversal of 21012001012 is 21010021012.

It can be written as a sum of positive squares in only one way, i.e., 13767267556 + 7244733456 = 117334^2 + 85116^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21012001012.

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 as a sum of consecutive naturals, namely, 2626500123 + ... + 2626500130.

Almost surely, 2^21012001012 is an apocalyptic number.

It is an amenable number.

21012001012 is a deficient number, since it is larger than the sum of its proper divisors (15759000766).

21012001012 is a wasteful number, since it uses less digits than its factorization.

21012001012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5253000257 (or 5253000255 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21012001012 its reverse (21010021012), we get a palindrome (42022022024).

The spelling of 21012001012 in words is "twenty-one billion, twelve million, one thousand, twelve".