640417859 has 2 divisors, whose sum is σ = 640417860. Its totient is φ = 640417858.

The previous prime is 640417853. The next prime is 640417873. The reversal of 640417859 is 958714046.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640417859 is a prime.

It is a super-2 number, since 2×640417859² = 820270068252287762, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640417853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320208929 + 320208930.

It is an arithmetic number, because the mean of its divisors is an integer number (320208930).

Almost surely, 2^640417859 is an apocalyptic number.

640417859 is a deficient number, since it is larger than the sum of its proper divisors (1).

640417859 is an equidigital number, since it uses as much as digits as its factorization.

640417859 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 44.

The square root of 640417859 is about 25306.4785973869. The cubic root of 640417859 is about 861.9613872774.

The spelling of 640417859 in words is "six hundred forty million, four hundred seventeen thousand, eight hundred fifty-nine".