21013019868 has 48 divisors (see below), whose sum is σ = 50831494560. Its totient is φ = 6748089600.

The previous prime is 21013019849. The next prime is 21013019879. The reversal of 21013019868 is 86891031012.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 94938 + ... + 225918.

It is an arithmetic number, because the mean of its divisors is an integer number (1058989470).

Almost surely, 2^21013019868 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21013019868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25415747280).

21013019868 is an abundant number, since it is smaller than the sum of its proper divisors (29818474692).

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

21013019868 is a wasteful number, since it uses less digits than its factorization.

21013019868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131478 (or 131476 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The spelling of 21013019868 in words is "twenty-one billion, thirteen million, nineteen thousand, eight hundred sixty-eight".