865621663 has 4 divisors (see below), whose sum is σ = 877479568. Its totient is φ = 853763760.

The previous prime is 865621637. The next prime is 865621699. The reversal of 865621663 is 366126568.

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 865621663 - 2²¹ = 863524511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865621613) 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 3 ways as a sum of consecutive naturals, for example, 5928843 + ... + 5928988.

It is an arithmetic number, because the mean of its divisors is an integer number (219369892).

Almost surely, 2^865621663 is an apocalyptic number.

865621663 is a deficient number, since it is larger than the sum of its proper divisors (11857905).

865621663 is a wasteful number, since it uses less digits than its factorization.

865621663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11857904.

The product of its digits is 311040, while the sum is 43.

The square root of 865621663 is about 29421.4490295770. The cubic root of 865621663 is about 953.0361452282.

The spelling of 865621663 in words is "eight hundred sixty-five million, six hundred twenty-one thousand, six hundred sixty-three".