645957863 has 2 divisors, whose sum is σ = 645957864. Its totient is φ = 645957862.

The previous prime is 645957821. The next prime is 645957883. The reversal of 645957863 is 368759546.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645957863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645957883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322978931 + 322978932.

It is an arithmetic number, because the mean of its divisors is an integer number (322978932).

Almost surely, 2^645957863 is an apocalyptic number.

645957863 is a deficient number, since it is larger than the sum of its proper divisors (1).

645957863 is an equidigital number, since it uses as much as digits as its factorization.

645957863 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5443200, while the sum is 53.

The square root of 645957863 is about 25415.7011117144. The cubic root of 645957863 is about 864.4397512605.

The spelling of 645957863 in words is "six hundred forty-five million, nine hundred fifty-seven thousand, eight hundred sixty-three".