1931778117979 has 8 divisors (see below), whose sum is σ = 1998413699760. Its totient is φ = 1865144039136.

The previous prime is 1931778117959. The next prime is 1931778118001. The reversal of 1931778117979 is 9797118771391.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1931778117979 - 2⁷ = 1931778117851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1931778117949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2653252 + ... + 3302014.

It is an arithmetic number, because the mean of its divisors is an integer number (249801712470).

Almost surely, 2^{1931778117979} is an apocalyptic number.

1931778117979 is a deficient number, since it is larger than the sum of its proper divisors (66635581781).

1931778117979 is a wasteful number, since it uses less digits than its factorization.

1931778117979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751469.

The product of its digits is 42007896, while the sum is 70.

The spelling of 1931778117979 in words is "one trillion, nine hundred thirty-one billion, seven hundred seventy-eight million, one hundred seventeen thousand, nine hundred seventy-nine".