640776285 has 32 divisors (see below), whose sum is σ = 1158480000. Its totient is φ = 335950848.

The previous prime is 640776271. The next prime is 640776289. The reversal of 640776285 is 582677046.

640776285 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 640776285 - 2⁶ = 640776221 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 640776285.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640776289) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32260 + ... + 48189.

It is an arithmetic number, because the mean of its divisors is an integer number (36202500).

Almost surely, 2^640776285 is an apocalyptic number.

It is an amenable number.

640776285 is a deficient number, since it is larger than the sum of its proper divisors (517703715).

640776285 is a wasteful number, since it uses less digits than its factorization.

640776285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80522 (or 80516 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The square root of 640776285 is about 25313.5593111676. The cubic root of 640776285 is about 862.1221634273.

The spelling of 640776285 in words is "six hundred forty million, seven hundred seventy-six thousand, two hundred eighty-five".