640941984 has 120 divisors (see below), whose sum is σ = 1903432608. Its totient is φ = 211559040.

The previous prime is 640941979. The next prime is 640942039. The reversal of 640941984 is 489149046.

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 in 19 ways as a sum of consecutive naturals, for example, 276189 + ... + 278499.

Almost surely, 2^640941984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640941984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (951716304).

640941984 is an abundant number, since it is smaller than the sum of its proper divisors (1262490624).

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

640941984 is a wasteful number, since it uses less digits than its factorization.

640941984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2440 (or 2423 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 640941984 is about 25316.8320293041. The cubic root of 640941984 is about 862.1964693756.

The spelling of 640941984 in words is "six hundred forty million, nine hundred forty-one thousand, nine hundred eighty-four".