19905367680 has 640 divisors, whose sum is σ = 78856493760. Its totient is φ = 4744396800.

The previous prime is 19905367663. The next prime is 19905367723. The reversal of 19905367680 is 8676350991.

19905367680 is a `hidden beast` number, since 19 + 90 + 536 + 7 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 38205820 + ... + 38206340.

Almost surely, 2^19905367680 is an apocalyptic number.

19905367680 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 19905367680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39428246880).

19905367680 is an abundant number, since it is smaller than the sum of its proper divisors (58951126080).

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

19905367680 is a wasteful number, since it uses less digits than its factorization.

19905367680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 2449440, while the sum is 54.

The spelling of 19905367680 in words is "nineteen billion, nine hundred five million, three hundred sixty-seven thousand, six hundred eighty".