640589040 has 320 divisors, whose sum is σ = 2716492800. Its totient is φ = 135115776.

The previous prime is 640589039. The next prime is 640589041. The reversal of 640589040 is 40985046.

640589040 is a `hidden beast` number, since 640 + 5 + 8 + 9 + 0 + 4 + 0 = 666.

640589040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640589039) and next prime (640589041).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 640588986 and 640589004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640589041) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 194931 + ... + 198189.

It is an arithmetic number, because the mean of its divisors is an integer number (8489040).

Almost surely, 2^640589040 is an apocalyptic number.

640589040 is a gapful number since it is divisible by the number (60) 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 640589040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1358246400).

640589040 is an abundant number, since it is smaller than the sum of its proper divisors (2075903760).

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

640589040 is a wasteful number, since it uses less digits than its factorization.

640589040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3301 (or 3289 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 640589040 is about 25309.8605290507. The cubic root of 640589040 is about 862.0381799868.

The spelling of 640589040 in words is "six hundred forty million, five hundred eighty-nine thousand, forty".