640617984 has 240 divisors, whose sum is σ = 2025703680. Its totient is φ = 201553920.

The previous prime is 640617983. The next prime is 640618067. The reversal of 640617984 is 489716046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640617983) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 2363769 + ... + 2364039.

It is an arithmetic number, because the mean of its divisors is an integer number (8440432).

Almost surely, 2^640617984 is an apocalyptic number.

640617984 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640617984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1012851840).

640617984 is an abundant number, since it is smaller than the sum of its proper divisors (1385085696).

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

640617984 is an equidigital number, since it uses as much as digits as its factorization.

640617984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 640617984 is about 25310.4323155493. The cubic root of 640617984 is about 862.0511630673.

It can be divided in two parts, 640617 and 984, that added together give a square (641601 = 801²).

The spelling of 640617984 in words is "six hundred forty million, six hundred seventeen thousand, nine hundred eighty-four".