1990681731979 has 2 divisors, whose sum is σ = 1990681731980. Its totient is φ = 1990681731978.

The previous prime is 1990681731917. The next prime is 1990681732007. The reversal of 1990681731979 is 9791371860991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1990681731979 - 2¹¹ = 1990681729931 is a prime.

It is a super-2 number, since 2×1990681731979² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1990681735979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995340865989 + 995340865990.

It is an arithmetic number, because the mean of its divisors is an integer number (995340865990).

Almost surely, 2^{1990681731979} is an apocalyptic number.

1990681731979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990681731979 is an equidigital number, since it uses as much as digits as its factorization.

1990681731979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46294416, while the sum is 70.

The spelling of 1990681731979 in words is "one trillion, nine hundred ninety billion, six hundred eighty-one million, seven hundred thirty-one thousand, nine hundred seventy-nine".