640185464 has 16 divisors (see below), whose sum is σ = 1239069120. Its totient is φ = 309767040.

The previous prime is 640185451. The next prime is 640185493. The reversal of 640185464 is 464581046.

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, 1290449 + ... + 1290944.

It is an arithmetic number, because the mean of its divisors is an integer number (77441820).

Almost surely, 2^640185464 is an apocalyptic number.

It is an amenable number.

640185464 is a deficient number, since it is larger than the sum of its proper divisors (598883656).

640185464 is a wasteful number, since it uses less digits than its factorization.

640185464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2581430 (or 2581426 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 38.

The square root of 640185464 is about 25301.8865699773. The cubic root of 640185464 is about 861.8571117387.

The spelling of 640185464 in words is "six hundred forty million, one hundred eighty-five thousand, four hundred sixty-four".