640727 has 2 divisors, whose sum is σ = 640728. Its totient is φ = 640726.

The previous prime is 640691. The next prime is 640733. The reversal of 640727 is 727046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640727 - 2⁶ = 640663 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 640696 and 640705.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640727.

It is not a weakly prime, because it can be changed into another prime (640777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320363 + 320364.

It is an arithmetic number, because the mean of its divisors is an integer number (320364).

2⁶⁴⁰⁷²⁷ is an apocalyptic number.

640727 is a deficient number, since it is larger than the sum of its proper divisors (1).

640727 is an equidigital number, since it uses as much as digits as its factorization.

640727 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 640727 is about 800.4542460378. The cubic root of 640727 is about 86.2100059623.

The spelling of 640727 in words is "six hundred forty thousand, seven hundred twenty-seven".