19491581917983 has 24 divisors (see below), whose sum is σ = 30196349549184. Its totient is φ = 10955455835040.

The previous prime is 19491581917897. The next prime is 19491581917991. The reversal of 19491581917983 is 38971918519491.

It is not a de Polignac number, because 19491581917983 - 2⁸ = 19491581917727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19491581917583) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 124642441 + ... + 124798722.

It is an arithmetic number, because the mean of its divisors is an integer number (1258181231216).

Almost surely, 2^{19491581917983} is an apocalyptic number.

19491581917983 is a deficient number, since it is larger than the sum of its proper divisors (10704767631201).

19491581917983 is an equidigital number, since it uses as much as digits as its factorization.

19491581917983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249441295 (or 249441234 counting only the distinct ones).

The product of its digits is 176359680, while the sum is 75.

The spelling of 19491581917983 in words is "nineteen trillion, four hundred ninety-one billion, five hundred eighty-one million, nine hundred seventeen thousand, nine hundred eighty-three".