865390221 has 12 divisors (see below), whose sum is σ = 1250533440. Its totient is φ = 576684360.

The previous prime is 865390217. The next prime is 865390223. The reversal of 865390221 is 122093568.

It is not a de Polignac number, because 865390221 - 2² = 865390217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865390223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3916 + ... + 41786.

It is an arithmetic number, because the mean of its divisors is an integer number (104211120).

Almost surely, 2^865390221 is an apocalyptic number.

It is an amenable number.

865390221 is a deficient number, since it is larger than the sum of its proper divisors (385143219).

865390221 is a wasteful number, since it uses less digits than its factorization.

865390221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40416 (or 40413 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 865390221 is about 29417.5155477141. The cubic root of 865390221 is about 952.9511996290.

The spelling of 865390221 in words is "eight hundred sixty-five million, three hundred ninety thousand, two hundred twenty-one".