863971221 has 16 divisors (see below), whose sum is σ = 1162692608. Its totient is φ = 570628800.

The previous prime is 863971189. The next prime is 863971247. The reversal of 863971221 is 122179368.

It is not a de Polignac number, because 863971221 - 2⁵ = 863971189 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 863971221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (863971261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 387891 + ... + 390111.

It is an arithmetic number, because the mean of its divisors is an integer number (72668288).

Almost surely, 2^863971221 is an apocalyptic number.

It is an amenable number.

863971221 is a deficient number, since it is larger than the sum of its proper divisors (298721387).

863971221 is a wasteful number, since it uses less digits than its factorization.

863971221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3372.

The product of its digits is 36288, while the sum is 39.

The square root of 863971221 is about 29393.3873685902. The cubic root of 863971221 is about 952.4300561064.

The spelling of 863971221 in words is "eight hundred sixty-three million, nine hundred seventy-one thousand, two hundred twenty-one".