640284644 has 12 divisors (see below), whose sum is σ = 1122250668. Its totient is φ = 319641600.

The previous prime is 640284587. The next prime is 640284647. The reversal of 640284644 is 446482046.

It can be written as a sum of positive squares in 2 ways, for example, as 523860544 + 116424100 = 22888^2 + 10790^2 .

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 640284598 and 640284607.

It is not an unprimeable number, because it can be changed into a prime (640284647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122297 + ... + 127424.

It is an arithmetic number, because the mean of its divisors is an integer number (93520889).

Almost surely, 2^640284644 is an apocalyptic number.

It is an amenable number.

640284644 is a deficient number, since it is larger than the sum of its proper divisors (481966024).

640284644 is a wasteful number, since it uses less digits than its factorization.

640284644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250366 (or 250364 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 38.

The square root of 640284644 is about 25303.8464269763. The cubic root of 640284644 is about 861.9016168493.

The spelling of 640284644 in words is "six hundred forty million, two hundred eighty-four thousand, six hundred forty-four".