864641605 has 4 divisors (see below), whose sum is σ = 1037569932. Its totient is φ = 691713280.

The previous prime is 864641597. The next prime is 864641623. The reversal of 864641605 is 506146468.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 100340289 + 764301316 = 10017^2 + 27646^2 .

It is not a de Polignac number, because 864641605 - 2³ = 864641597 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86464156 + ... + 86464165.

It is an arithmetic number, because the mean of its divisors is an integer number (259392483).

Almost surely, 2^864641605 is an apocalyptic number.

It is an amenable number.

864641605 is a deficient number, since it is larger than the sum of its proper divisors (172928327).

864641605 is a wasteful number, since it uses less digits than its factorization.

864641605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172928326.

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 864641605 is about 29404.7888106682. The cubic root of 864641605 is about 952.6763331364.

The spelling of 864641605 in words is "eight hundred sixty-four million, six hundred forty-one thousand, six hundred five".