640499 has 2 divisors, whose sum is σ = 640500. Its totient is φ = 640498.

The previous prime is 640483. The next prime is 640529. The reversal of 640499 is 994046.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640499 - 2⁴ = 640483 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320249 + 320250.

It is an arithmetic number, because the mean of its divisors is an integer number (320250).

2⁶⁴⁰⁴⁹⁹ is an apocalyptic number.

640499 is a deficient number, since it is larger than the sum of its proper divisors (1).

640499 is an equidigital number, since it uses as much as digits as its factorization.

640499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 640499 is about 800.3118142324. The cubic root of 640499 is about 86.1997789268.

The spelling of 640499 in words is "six hundred forty thousand, four hundred ninety-nine".