640532444 has 12 divisors (see below), whose sum is σ = 1126566000. Its totient is φ = 318656448.

The previous prime is 640532369. The next prime is 640532471. The reversal of 640532444 is 444235046.

It is a super-2 number, since 2×640532444² = 820563623633226272, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640532444.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 401549 + ... + 403140.

It is an arithmetic number, because the mean of its divisors is an integer number (93880500).

Almost surely, 2^640532444 is an apocalyptic number.

It is an amenable number.

640532444 is a deficient number, since it is larger than the sum of its proper divisors (486033556).

640532444 is a wasteful number, since it uses less digits than its factorization.

640532444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804892 (or 804890 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 32.

The square root of 640532444 is about 25308.7424420891. The cubic root of 640532444 is about 862.0127922334.

The spelling of 640532444 in words is "six hundred forty million, five hundred thirty-two thousand, four hundred forty-four".