640180556 has 6 divisors (see below), whose sum is σ = 1120315980. Its totient is φ = 320090276.

The previous prime is 640180553. The next prime is 640180589. The reversal of 640180556 is 655081046.

It is a happy number.

It is a super-2 number, since 2×640180556² = 819662288560938272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640180553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80022566 + ... + 80022573.

It is an arithmetic number, because the mean of its divisors is an integer number (186719330).

Almost surely, 2^640180556 is an apocalyptic number.

It is an amenable number.

640180556 is a deficient number, since it is larger than the sum of its proper divisors (480135424).

640180556 is a wasteful number, since it uses less digits than its factorization.

640180556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160045143 (or 160045141 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 640180556 is about 25301.7895809763. The cubic root of 640180556 is about 861.8549092491.

The spelling of 640180556 in words is "six hundred forty million, one hundred eighty thousand, five hundred fifty-six".