640396703 has 4 divisors (see below), whose sum is σ = 657704760. Its totient is φ = 623088648.

The previous prime is 640396693. The next prime is 640396723. The reversal of 640396703 is 307693046.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640396703 - 2⁶ = 640396639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640396723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8653973 + ... + 8654046.

It is an arithmetic number, because the mean of its divisors is an integer number (164426190).

Almost surely, 2^640396703 is an apocalyptic number.

640396703 is a deficient number, since it is larger than the sum of its proper divisors (17308057).

640396703 is a wasteful number, since it uses less digits than its factorization.

640396703 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17308056.

The product of its (nonzero) digits is 81648, while the sum is 38.

The square root of 640396703 is about 25306.0605982045. The cubic root of 640396703 is about 861.9518956329.

The spelling of 640396703 in words is "six hundred forty million, three hundred ninety-six thousand, seven hundred three".