640267 has 2 divisors, whose sum is σ = 640268. Its totient is φ = 640266.

The previous prime is 640261. The next prime is 640279. The reversal of 640267 is 762046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640267 - 2³ = 640259 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640267.

It is not a weakly prime, because it can be changed into another prime (640261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320133 + 320134.

It is an arithmetic number, because the mean of its divisors is an integer number (320134).

2⁶⁴⁰²⁶⁷ is an apocalyptic number.

640267 is a deficient number, since it is larger than the sum of its proper divisors (1).

640267 is an equidigital number, since it uses as much as digits as its factorization.

640267 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 640267 is about 800.1668575991. The cubic root of 640267 is about 86.1893699781.

The spelling of 640267 in words is "six hundred forty thousand, two hundred sixty-seven".