6641137861 has 2 divisors, whose sum is σ = 6641137862. Its totient is φ = 6641137860.

The previous prime is 6641137859. The next prime is 6641137957. The reversal of 6641137861 is 1687311466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6627588100 + 13549761 = 81410^2 + 3681^2 .

It is a cyclic number.

It is not a de Polignac number, because 6641137861 - 2¹ = 6641137859 is a prime.

Together with 6641137859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6641137831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320568930 + 3320568931.

It is an arithmetic number, because the mean of its divisors is an integer number (3320568931).

Almost surely, 2^6641137861 is an apocalyptic number.

It is an amenable number.

6641137861 is a deficient number, since it is larger than the sum of its proper divisors (1).

6641137861 is an equidigital number, since it uses as much as digits as its factorization.

6641137861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 6641137861 is about 81493.1767757277. The cubic root of 6641137861 is about 1879.6666321715. Note that the first 4 decimals are identical.

The spelling of 6641137861 in words is "six billion, six hundred forty-one million, one hundred thirty-seven thousand, eight hundred sixty-one".