640656622 has 8 divisors (see below), whose sum is σ = 961094376. Its totient is φ = 320291832.

The previous prime is 640656617. The next prime is 640656623. The reversal of 640656622 is 226656046.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640656623) 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, 18568 + ... + 40324.

It is an arithmetic number, because the mean of its divisors is an integer number (120136797).

Almost surely, 2^640656622 is an apocalyptic number.

640656622 is a deficient number, since it is larger than the sum of its proper divisors (320437754).

640656622 is a wasteful number, since it uses less digits than its factorization.

640656622 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36482.

The product of its (nonzero) digits is 103680, while the sum is 37.

The square root of 640656622 is about 25311.1955861433. The cubic root of 640656622 is about 862.0684938656.

It can be divided in two parts, 640656 and 622, that added together give a triangular number (641278 = T₁₁₃₂).

The spelling of 640656622 in words is "six hundred forty million, six hundred fifty-six thousand, six hundred twenty-two".