640166736 has 40 divisors (see below), whose sum is σ = 1804107744. Its totient is φ = 193989760.

The previous prime is 640166699. The next prime is 640166749. The reversal of 640166736 is 637661046.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 640166694 and 640166703.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 605691 + ... + 606746.

Almost surely, 2^640166736 is an apocalyptic number.

640166736 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

640166736 is an abundant number, since it is smaller than the sum of its proper divisors (1163941008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640166736 is a wasteful number, since it uses less digits than its factorization.

640166736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212459 (or 1212453 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 640166736 is about 25301.5164762905. The cubic root of 640166736 is about 861.8487073943.

It can be divided in two parts, 6401 and 66736, that added together give a palindrome (73137).

The spelling of 640166736 in words is "six hundred forty million, one hundred sixty-six thousand, seven hundred thirty-six".