640811085 has 8 divisors (see below), whose sum is σ = 1025297760. Its totient is φ = 341765904.

The previous prime is 640811071. The next prime is 640811111. The reversal of 640811085 is 580118046.

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

It is not a de Polignac number, because 640811085 - 2⁵ = 640811053 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21360355 + ... + 21360384.

It is an arithmetic number, because the mean of its divisors is an integer number (128162220).

Almost surely, 2^640811085 is an apocalyptic number.

It is an amenable number.

640811085 is a deficient number, since it is larger than the sum of its proper divisors (384486675).

640811085 is a wasteful number, since it uses less digits than its factorization.

640811085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42720747.

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 640811085 is about 25314.2466804762. The cubic root of 640811085 is about 862.1377701785.

The spelling of 640811085 in words is "six hundred forty million, eight hundred eleven thousand, eighty-five".