21001031012 has 24 divisors (see below), whose sum is σ = 39665516856. Its totient is φ = 9671563008.

The previous prime is 21001030993. The next prime is 21001031063. The reversal of 21001031012 is 21013010012.

It can be written as a sum of positive squares in 4 ways, for example, as 26460736 + 20974570276 = 5144^2 + 144826^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21001030984 and 21001031002.

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, 418103 + ... + 465630.

It is an arithmetic number, because the mean of its divisors is an integer number (1652729869).

Almost surely, 2^21001031012 is an apocalyptic number.

It is an amenable number.

21001031012 is a deficient number, since it is larger than the sum of its proper divisors (18664485844).

21001031012 is a wasteful number, since it uses less digits than its factorization.

21001031012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 884207 (or 884205 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21001031012 its reverse (21013010012), we get a palindrome (42014041024).

The spelling of 21001031012 in words is "twenty-one billion, one million, thirty-one thousand, twelve".