640432255 has 16 divisors (see below), whose sum is σ = 794098944. Its totient is φ = 495325440.

The previous prime is 640432207. The next prime is 640432271. The reversal of 640432255 is 552234046.

It is not a de Polignac number, because 640432255 - 2⁷ = 640432127 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270537 + ... + 272893.

It is an arithmetic number, because the mean of its divisors is an integer number (49631184).

Almost surely, 2^640432255 is an apocalyptic number.

640432255 is a deficient number, since it is larger than the sum of its proper divisors (153666689).

640432255 is a wasteful number, since it uses less digits than its factorization.

640432255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4146.

The product of its (nonzero) digits is 28800, while the sum is 31.

The square root of 640432255 is about 25306.7630288822. The cubic root of 640432255 is about 861.9678459268.

The spelling of 640432255 in words is "six hundred forty million, four hundred thirty-two thousand, two hundred fifty-five".