6391958081 has 2 divisors, whose sum is σ = 6391958082. Its totient is φ = 6391958080.

The previous prime is 6391958071. The next prime is 6391958101. The reversal of 6391958081 is 1808591936.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3376191025 + 3015767056 = 58105^2 + 54916^2 .

It is a cyclic number.

It is not a de Polignac number, because 6391958081 - 2¹⁰ = 6391957057 is a prime.

It is a super-3 number, since 3×6391958081³ (a number of 30 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (6391958021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3195979040 + 3195979041.

It is an arithmetic number, because the mean of its divisors is an integer number (3195979041).

Almost surely, 2^6391958081 is an apocalyptic number.

It is an amenable number.

6391958081 is a deficient number, since it is larger than the sum of its proper divisors (1).

6391958081 is an equidigital number, since it uses as much as digits as its factorization.

6391958081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 50.

The square root of 6391958081 is about 79949.7222071472. The cubic root of 6391958081 is about 1855.8575558017.

The spelling of 6391958081 in words is "six billion, three hundred ninety-one million, nine hundred fifty-eight thousand, eighty-one".