19987131264 has 128 divisors (see below), whose sum is σ = 55032998400. Its totient is φ = 6422913024.

The previous prime is 19987131247. The next prime is 19987131271. The reversal of 19987131264 is 46213178991.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

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, 1200952 + ... + 1217480.

It is an arithmetic number, because the mean of its divisors is an integer number (429945300).

Almost surely, 2^19987131264 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 19987131264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27516499200).

19987131264 is an abundant number, since it is smaller than the sum of its proper divisors (35045867136).

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

19987131264 is a wasteful number, since it uses less digits than its factorization.

19987131264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16660 (or 16648 counting only the distinct ones).

The product of its digits is 653184, while the sum is 51.

The spelling of 19987131264 in words is "nineteen billion, nine hundred eighty-seven million, one hundred thirty-one thousand, two hundred sixty-four".