640793923 has 12 divisors (see below), whose sum is σ = 813178872. Its totient is φ = 499319520.

The previous prime is 640793921. The next prime is 640793929. The reversal of 640793923 is 329397046.

640793923 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640793923 - 2¹ = 640793921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640793923.

It is not an unprimeable number, because it can be changed into a prime (640793921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 593890 + ... + 594967.

It is an arithmetic number, because the mean of its divisors is an integer number (67764906).

Almost surely, 2^640793923 is an apocalyptic number.

640793923 is a deficient number, since it is larger than the sum of its proper divisors (172384949).

640793923 is a wasteful number, since it uses less digits than its factorization.

640793923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188882 (or 1188875 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 43.

The square root of 640793923 is about 25313.9076991286. The cubic root of 640793923 is about 862.1300736093.

The spelling of 640793923 in words is "six hundred forty million, seven hundred ninety-three thousand, nine hundred twenty-three".