645643267 has 2 divisors, whose sum is σ = 645643268. Its totient is φ = 645643266.

The previous prime is 645643261. The next prime is 645643279. The reversal of 645643267 is 762346546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645643267 - 2²³ = 637254659 is a prime.

It is not a weakly prime, because it can be changed into another prime (645643261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322821633 + 322821634.

It is an arithmetic number, because the mean of its divisors is an integer number (322821634).

Almost surely, 2^645643267 is an apocalyptic number.

645643267 is a deficient number, since it is larger than the sum of its proper divisors (1).

645643267 is an equidigital number, since it uses as much as digits as its factorization.

645643267 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 43.

The square root of 645643267 is about 25409.5113490992. The cubic root of 645643267 is about 864.2993946088.

The spelling of 645643267 in words is "six hundred forty-five million, six hundred forty-three thousand, two hundred sixty-seven".