640566450 has 36 divisors (see below), whose sum is σ = 1720989738. Its totient is φ = 170817600.

The previous prime is 640566419. The next prime is 640566457. The reversal of 640566450 is 54665046.

It is a happy number.

640566450 is a `hidden beast` number, since 6 + 4 + 0 + 5 + 6 + 645 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 482636961 + 157929489 = 21969^2 + 12567^2 .

It is a super-3 number, since 3×640566450³ (a number of 27 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640566457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 711291 + ... + 712190.

Almost surely, 2^640566450 is an apocalyptic number.

640566450 is an abundant number, since it is smaller than the sum of its proper divisors (1080423288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640566450 is a wasteful number, since it uses less digits than its factorization.

640566450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1423499 (or 1423491 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 640566450 is about 25309.4142563592. The cubic root of 640566450 is about 862.0280467760.

The spelling of 640566450 in words is "six hundred forty million, five hundred sixty-six thousand, four hundred fifty".