19664048640 has 160 divisors (see below), whose sum is σ = 63930461760. Its totient is φ = 5154750464.

The previous prime is 19664048629. The next prime is 19664048653. The reversal of 19664048640 is 4684046691.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (160).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 19664048640.

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, 431422 + ... + 474818.

It is an arithmetic number, because the mean of its divisors is an integer number (399565386).

Almost surely, 2^19664048640 is an apocalyptic number.

19664048640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19664048640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31965230880).

19664048640 is an abundant number, since it is smaller than the sum of its proper divisors (44266413120).

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

19664048640 is an equidigital number, since it uses as much as digits as its factorization.

19664048640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43482 (or 43466 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 48.

The spelling of 19664048640 in words is "nineteen billion, six hundred sixty-four million, forty-eight thousand, six hundred forty".