640000628 has 12 divisors (see below), whose sum is σ = 1121118180. Its totient is φ = 319681152.

The previous prime is 640000607. The next prime is 640000639. The reversal of 640000628 is 826000046.

It can be written as a sum of positive squares in 2 ways, for example, as 479522404 + 160478224 = 21898^2 + 12668^2 .

It is a junction number, because it is equal to n+sod(n) for n = 640000597 and 640000606.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 75251 + ... + 83322.

It is an arithmetic number, because the mean of its divisors is an integer number (93426515).

Almost surely, 2^640000628 is an apocalyptic number.

It is an amenable number.

640000628 is a deficient number, since it is larger than the sum of its proper divisors (481117552).

640000628 is a wasteful number, since it uses less digits than its factorization.

640000628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159586 (or 159584 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 640000628 is about 25298.2336932838. The cubic root of 640000628 is about 861.7741578845.

The spelling of 640000628 in words is "six hundred forty million, six hundred twenty-eight", and thus it is an aban number.