640055520 has 480 divisors, whose sum is σ = 2535714720. Its totient is φ = 150958080.

The previous prime is 640055497. The next prime is 640055587. The reversal of 640055520 is 25550046.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (27).

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 79 ways as a sum of consecutive naturals, for example, 4885855 + ... + 4885985.

It is an arithmetic number, because the mean of its divisors is an integer number (5282739).

Almost surely, 2^640055520 is an apocalyptic number.

640055520 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 640055520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1267857360).

640055520 is an abundant number, since it is smaller than the sum of its proper divisors (1895659200).

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

640055520 is a wasteful number, since it uses less digits than its factorization.

640055520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The square root of 640055520 is about 25299.3185678982. The cubic root of 640055520 is about 861.7987949201.

The spelling of 640055520 in words is "six hundred forty million, fifty-five thousand, five hundred twenty".