6311261581 has 2 divisors, whose sum is σ = 6311261582. Its totient is φ = 6311261580.

The previous prime is 6311261549. The next prime is 6311261599. The reversal of 6311261581 is 1851621136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4718453481 + 1592808100 = 68691^2 + 39910^2 .

It is a cyclic number.

It is not a de Polignac number, because 6311261581 - 2⁵ = 6311261549 is a prime.

It is a super-2 number, since 2×6311261581² = 79664045487613239122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6311261381) 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, 3155630790 + 3155630791.

It is an arithmetic number, because the mean of its divisors is an integer number (3155630791).

Almost surely, 2^6311261581 is an apocalyptic number.

It is an amenable number.

6311261581 is a deficient number, since it is larger than the sum of its proper divisors (1).

6311261581 is an equidigital number, since it uses as much as digits as its factorization.

6311261581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 34.

The square root of 6311261581 is about 79443.4489495515. The cubic root of 6311261581 is about 1848.0145810905.

The spelling of 6311261581 in words is "six billion, three hundred eleven million, two hundred sixty-one thousand, five hundred eighty-one".