640492 has 12 divisors (see below), whose sum is σ = 1186920. Its totient is φ = 301376.

The previous prime is 640483. The next prime is 640499. The reversal of 640492 is 294046.

It is not an unprimeable number, because it can be changed into a prime (640499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4642 + ... + 4777.

It is an arithmetic number, because the mean of its divisors is an integer number (98910).

2⁶⁴⁰⁴⁹² is an apocalyptic number.

It is an amenable number.

640492 is a deficient number, since it is larger than the sum of its proper divisors (546428).

640492 is a wasteful number, since it uses less digits than its factorization.

640492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9440 (or 9438 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 640492 is about 800.3074409250. The cubic root of 640492 is about 86.1994649005.

The spelling of 640492 in words is "six hundred forty thousand, four hundred ninety-two".