640575477 has 6 divisors (see below), whose sum is σ = 925275702. Its totient is φ = 427050312.

The previous prime is 640575473. The next prime is 640575499. The reversal of 640575477 is 774575046.

640575477 is a `hidden beast` number, since 6 + 4 + 0 + 575 + 4 + 77 = 666.

It can be written as a sum of positive squares in only one way, i.e., 533887236 + 106688241 = 23106^2 + 10329^2 .

It is not a de Polignac number, because 640575477 - 2² = 640575473 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640575473) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35587518 + ... + 35587535.

It is an arithmetic number, because the mean of its divisors is an integer number (154212617).

Almost surely, 2^640575477 is an apocalyptic number.

It is an amenable number.

640575477 is a deficient number, since it is larger than the sum of its proper divisors (284700225).

640575477 is a wasteful number, since it uses less digits than its factorization.

640575477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71175059 (or 71175056 counting only the distinct ones).

The product of its (nonzero) digits is 823200, while the sum is 45.

The square root of 640575477 is about 25309.5925885819. The cubic root of 640575477 is about 862.0320960517.

The spelling of 640575477 in words is "six hundred forty million, five hundred seventy-five thousand, four hundred seventy-seven".