640424718 has 80 divisors (see below), whose sum is σ = 1466868480. Its totient is φ = 208797264.

The previous prime is 640424699. The next prime is 640424737. The reversal of 640424718 is 817424046.

640424718 is a `hidden beast` number, since 6 + 404 + 247 + 1 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (640424699) and next prime (640424737).

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 39 ways as a sum of consecutive naturals, for example, 2085921 + ... + 2086227.

It is an arithmetic number, because the mean of its divisors is an integer number (18335856).

Almost surely, 2^640424718 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640424718, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (733434240).

640424718 is an abundant number, since it is smaller than the sum of its proper divisors (826443762).

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

640424718 is a wasteful number, since it uses less digits than its factorization.

640424718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563 (or 554 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The square root of 640424718 is about 25306.6141156813. The cubic root of 640424718 is about 861.9644645245.

The spelling of 640424718 in words is "six hundred forty million, four hundred twenty-four thousand, seven hundred eighteen".