641819557 has 2 divisors, whose sum is σ = 641819558. Its totient is φ = 641819556.

The previous prime is 641819543. The next prime is 641819587. The reversal of 641819557 is 755918146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 607080321 + 34739236 = 24639^2 + 5894^2 .

It is a cyclic number.

It is not a de Polignac number, because 641819557 - 2⁷ = 641819429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641819537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320909778 + 320909779.

It is an arithmetic number, because the mean of its divisors is an integer number (320909779).

Almost surely, 2^641819557 is an apocalyptic number.

It is an amenable number.

641819557 is a deficient number, since it is larger than the sum of its proper divisors (1).

641819557 is an equidigital number, since it uses as much as digits as its factorization.

641819557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 302400, while the sum is 46.

The square root of 641819557 is about 25334.1579098260. The cubic root of 641819557 is about 862.5897942499.

The spelling of 641819557 in words is "six hundred forty-one million, eight hundred nineteen thousand, five hundred fifty-seven".