864841221 has 24 divisors (see below), whose sum is σ = 1392318720. Its totient is φ = 514083456.

The previous prime is 864841199. The next prime is 864841247. The reversal of 864841221 is 122148468.

864841221 is a `hidden beast` number, since 8 + 648 + 4 + 1 + 2 + 2 + 1 = 666.

It is not a de Polignac number, because 864841221 - 2⁵ = 864841189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864841291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 145845 + ... + 151658.

It is an arithmetic number, because the mean of its divisors is an integer number (58013280).

Almost surely, 2^864841221 is an apocalyptic number.

It is an amenable number.

864841221 is a deficient number, since it is larger than the sum of its proper divisors (527477499).

864841221 is a wasteful number, since it uses less digits than its factorization.

864841221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297545 (or 297542 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 864841221 is about 29408.1828918415. The cubic root of 864841221 is about 952.7496408919.

Adding to 864841221 its reverse (122148468), we get a palindrome (986989689).

The spelling of 864841221 in words is "eight hundred sixty-four million, eight hundred forty-one thousand, two hundred twenty-one".