640858811 has 8 divisors (see below), whose sum is σ = 644467824. Its totient is φ = 637257600.

The previous prime is 640858807. The next prime is 640858831. The reversal of 640858811 is 118858046.

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 640858811 - 2² = 640858807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640858831) by changing a digit.

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, 243575 + ... + 246191.

It is an arithmetic number, because the mean of its divisors is an integer number (80558478).

Almost surely, 2^640858811 is an apocalyptic number.

640858811 is a deficient number, since it is larger than the sum of its proper divisors (3609013).

640858811 is a wasteful number, since it uses less digits than its factorization.

640858811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3901.

The product of its (nonzero) digits is 61440, while the sum is 41.

The square root of 640858811 is about 25315.1893336787. The cubic root of 640858811 is about 862.1591729323.

The spelling of 640858811 in words is "six hundred forty million, eight hundred fifty-eight thousand, eight hundred eleven".