640251000 has 256 divisors, whose sum is σ = 2318284800. Its totient is φ = 163152000.

The previous prime is 640250981. The next prime is 640251041. The reversal of 640251000 is 152046.

It is a happy number.

640251000 is a `hidden beast` number, since 640 + 25 + 1 + 0 + 0 + 0 = 666.

It is a super-3 number, since 3×640251000³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 620485 + ... + 621515.

It is an arithmetic number, because the mean of its divisors is an integer number (9055800).

Almost surely, 2^640251000 is an apocalyptic number.

640251000 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 640251000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1159142400).

640251000 is an abundant number, since it is smaller than the sum of its proper divisors (1678033800).

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

640251000 is a wasteful number, since it uses less digits than its factorization.

640251000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1084 (or 1064 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 640251000 is about 25303.1816181286. The cubic root of 640251000 is about 861.8865202688.

It can be divided in two parts, 64025 and 1000, that added together give a square (65025 = 255²).

The spelling of 640251000 in words is "six hundred forty million, two hundred fifty-one thousand".