20981270868 has 96 divisors (see below), whose sum is σ = 52630591104. Its totient is φ = 6481993728.

The previous prime is 20981270857. The next prime is 20981270873. The reversal of 20981270868 is 86807218902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 20981270868.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5704246 + ... + 5707922.

It is an arithmetic number, because the mean of its divisors is an integer number (548235324).

Almost surely, 2^20981270868 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 20981270868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26315295552).

20981270868 is an abundant number, since it is smaller than the sum of its proper divisors (31649320236).

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

20981270868 is a wasteful number, since it uses less digits than its factorization.

20981270868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4121 (or 4119 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 51.

The spelling of 20981270868 in words is "twenty billion, nine hundred eighty-one million, two hundred seventy thousand, eight hundred sixty-eight".