1982317991 has 2 divisors, whose sum is σ = 1982317992. Its totient is φ = 1982317990.

The previous prime is 1982317969. The next prime is 1982318057. The reversal of 1982317991 is 1997132891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1982317991 - 2³⁰ = 908576167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1982317901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 991158995 + 991158996.

It is an arithmetic number, because the mean of its divisors is an integer number (991158996).

Almost surely, 2^1982317991 is an apocalyptic number.

1982317991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1982317991 is an equidigital number, since it uses as much as digits as its factorization.

1982317991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 50.

The square root of 1982317991 is about 44523.2297907508. The cubic root of 1982317991 is about 1256.1970644229.

The spelling of 1982317991 in words is "one billion, nine hundred eighty-two million, three hundred seventeen thousand, nine hundred ninety-one".