640527697 has 4 divisors (see below), whose sum is σ = 640790640. Its totient is φ = 640264756.

The previous prime is 640527689. The next prime is 640527721. The reversal of 640527697 is 796725046.

640527697 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 640527697 - 2³ = 640527689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640527637) 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, 127783 + ... + 132700.

It is an arithmetic number, because the mean of its divisors is an integer number (160197660).

Almost surely, 2^640527697 is an apocalyptic number.

It is an amenable number.

640527697 is a deficient number, since it is larger than the sum of its proper divisors (262943).

640527697 is a wasteful number, since it uses less digits than its factorization.

640527697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262942.

The product of its (nonzero) digits is 635040, while the sum is 46.

The square root of 640527697 is about 25308.6486600925. The cubic root of 640527697 is about 862.0106627629.

The spelling of 640527697 in words is "six hundred forty million, five hundred twenty-seven thousand, six hundred ninety-seven".