6403391861 has 2 divisors, whose sum is σ = 6403391862. Its totient is φ = 6403391860.

The previous prime is 6403391833. The next prime is 6403391867. The reversal of 6403391861 is 1681933046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5068585636 + 1334806225 = 71194^2 + 36535^2 .

It is a cyclic number.

It is not a de Polignac number, because 6403391861 - 2¹⁰ = 6403390837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6403391867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3201695930 + 3201695931.

It is an arithmetic number, because the mean of its divisors is an integer number (3201695931).

Almost surely, 2^6403391861 is an apocalyptic number.

It is an amenable number.

6403391861 is a deficient number, since it is larger than the sum of its proper divisors (1).

6403391861 is an equidigital number, since it uses as much as digits as its factorization.

6403391861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 41.

The square root of 6403391861 is about 80021.1963232243. The cubic root of 6403391861 is about 1856.9634676889.

The spelling of 6403391861 in words is "six billion, four hundred three million, three hundred ninety-one thousand, eight hundred sixty-one".