618641857 has 2 divisors, whose sum is σ = 618641858. Its totient is φ = 618641856.

The previous prime is 618641851. The next prime is 618641869. The reversal of 618641857 is 758146816.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 390299536 + 228342321 = 19756^2 + 15111^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-618641857 is a prime.

It is not a weakly prime, because it can be changed into another prime (618641851) 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, 309320928 + 309320929.

It is an arithmetic number, because the mean of its divisors is an integer number (309320929).

Almost surely, 2^618641857 is an apocalyptic number.

It is an amenable number.

618641857 is a deficient number, since it is larger than the sum of its proper divisors (1).

618641857 is an equidigital number, since it uses as much as digits as its factorization.

618641857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 46.

The square root of 618641857 is about 24872.5120765877. The cubic root of 618641857 is about 852.0788135083.

The spelling of 618641857 in words is "six hundred eighteen million, six hundred forty-one thousand, eight hundred fifty-seven".