640135855 has 8 divisors (see below), whose sum is σ = 782656992. Its totient is φ = 502446048.

The previous prime is 640135843. The next prime is 640135861. The reversal of 640135855 is 558531046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640135855 - 2²¹ = 638038703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1207539 + ... + 1208068.

It is an arithmetic number, because the mean of its divisors is an integer number (97832124).

Almost surely, 2^640135855 is an apocalyptic number.

640135855 is a deficient number, since it is larger than the sum of its proper divisors (142521137).

640135855 is a wasteful number, since it uses less digits than its factorization.

640135855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2415665.

The product of its (nonzero) digits is 72000, while the sum is 37.

The square root of 640135855 is about 25300.9062090669. The cubic root of 640135855 is about 861.8348489330.

The spelling of 640135855 in words is "six hundred forty million, one hundred thirty-five thousand, eight hundred fifty-five".