21001311012 has 48 divisors (see below), whose sum is σ = 56602469952. Its totient is φ = 5989678080.

The previous prime is 21001310999. The next prime is 21001311049. The reversal of 21001311012 is 21011310012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4677193 + ... + 4681680.

It is an arithmetic number, because the mean of its divisors is an integer number (1179218124).

Almost surely, 2^21001311012 is an apocalyptic number.

21001311012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21001311012 is an abundant number, since it is smaller than the sum of its proper divisors (35601158940).

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

21001311012 is a wasteful number, since it uses less digits than its factorization.

21001311012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9358908 (or 9358906 counting only the distinct ones).

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

Adding to 21001311012 its reverse (21011310012), we get a palindrome (42012621024).

The spelling of 21001311012 in words is "twenty-one billion, one million, three hundred eleven thousand, twelve".