640662586 has 4 divisors (see below), whose sum is σ = 960993882. Its totient is φ = 320331292.

The previous prime is 640662541. The next prime is 640662599. The reversal of 640662586 is 685266046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 637310025 + 3352561 = 25245^2 + 1831^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 160165645 + ... + 160165648.

Almost surely, 2^640662586 is an apocalyptic number.

640662586 is a deficient number, since it is larger than the sum of its proper divisors (320331296).

640662586 is a wasteful number, since it uses less digits than its factorization.

640662586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320331295.

The product of its (nonzero) digits is 414720, while the sum is 43.

The square root of 640662586 is about 25311.3133993477. The cubic root of 640662586 is about 862.0711689131.

The spelling of 640662586 in words is "six hundred forty million, six hundred sixty-two thousand, five hundred eighty-six".