646157983 has 4 divisors (see below), whose sum is σ = 655802200. Its totient is φ = 636513768.

The previous prime is 646157977. The next prime is 646157989. The reversal of 646157983 is 389751646.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (646157977) and next prime (646157989).

It is a cyclic number.

It is not a de Polignac number, because 646157983 - 2⁵ = 646157951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646157989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4822008 + ... + 4822141.

It is an arithmetic number, because the mean of its divisors is an integer number (163950550).

Almost surely, 2^646157983 is an apocalyptic number.

646157983 is a deficient number, since it is larger than the sum of its proper divisors (9644217).

646157983 is an equidigital number, since it uses as much as digits as its factorization.

646157983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9644216.

The product of its digits is 1088640, while the sum is 49.

The square root of 646157983 is about 25419.6377432882. The cubic root of 646157983 is about 864.5290108607.

The spelling of 646157983 in words is "six hundred forty-six million, one hundred fifty-seven thousand, nine hundred eighty-three".