864840643 has 4 divisors (see below), whose sum is σ = 915713640. Its totient is φ = 813967648.

The previous prime is 864840637. The next prime is 864840659. The reversal of 864840643 is 346048468.

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

It is a cyclic number.

It is not a de Polignac number, because 864840643 - 2⁵ = 864840611 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 864840643.

It is not an unprimeable number, because it can be changed into a prime (864840143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25436473 + ... + 25436506.

It is an arithmetic number, because the mean of its divisors is an integer number (228928410).

Almost surely, 2^864840643 is an apocalyptic number.

864840643 is a deficient number, since it is larger than the sum of its proper divisors (50872997).

864840643 is a wasteful number, since it uses less digits than its factorization.

864840643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50872996.

The product of its (nonzero) digits is 442368, while the sum is 43.

The square root of 864840643 is about 29408.1730646431. The cubic root of 864840643 is about 952.7494286413.

The spelling of 864840643 in words is "eight hundred sixty-four million, eight hundred forty thousand, six hundred forty-three".