640565476 has 6 divisors (see below), whose sum is σ = 1120989590. Its totient is φ = 320282736.

The previous prime is 640565461. The next prime is 640565477. The reversal of 640565476 is 674565046.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 594189376 + 46376100 = 24376^2 + 6810^2 .

It is not an unprimeable number, because it can be changed into a prime (640565477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80070681 + ... + 80070688.

Almost surely, 2^640565476 is an apocalyptic number.

It is an amenable number.

640565476 is a deficient number, since it is larger than the sum of its proper divisors (480424114).

640565476 is a wasteful number, since it uses less digits than its factorization.

640565476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160141373 (or 160141371 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 43.

The square root of 640565476 is about 25309.3950145001. The cubic root of 640565476 is about 862.0276098628.

The spelling of 640565476 in words is "six hundred forty million, five hundred sixty-five thousand, four hundred seventy-six".