19901191680 has 120 divisors (see below), whose sum is σ = 68923503792. Its totient is φ = 5306978304.

The previous prime is 19901191663. The next prime is 19901191691. The reversal of 19901191680 is 8619110991.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 408844 + ... + 454923.

Almost surely, 2^19901191680 is an apocalyptic number.

19901191680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19901191680 is an abundant number, since it is smaller than the sum of its proper divisors (49022312112).

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

19901191680 is an equidigital number, since it uses as much as digits as its factorization.

19901191680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863796 (or 863777 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 45.

The spelling of 19901191680 in words is "nineteen billion, nine hundred one million, one hundred ninety-one thousand, six hundred eighty".