640423265 has 8 divisors (see below), whose sum is σ = 793298688. Its totient is φ = 495811440.

The previous prime is 640423261. The next prime is 640423283. The reversal of 640423265 is 562324046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640423265 - 2² = 640423261 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640423261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2065727 + ... + 2066036.

It is an arithmetic number, because the mean of its divisors is an integer number (99162336).

Almost surely, 2^640423265 is an apocalyptic number.

It is an amenable number.

640423265 is a deficient number, since it is larger than the sum of its proper divisors (152875423).

640423265 is a wasteful number, since it uses less digits than its factorization.

640423265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4131799.

The product of its (nonzero) digits is 34560, while the sum is 32.

The square root of 640423265 is about 25306.5854077550. The cubic root of 640423265 is about 861.9638126471.

The spelling of 640423265 in words is "six hundred forty million, four hundred twenty-three thousand, two hundred sixty-five".