865471221 has 12 divisors (see below), whose sum is σ = 1250952300. Its totient is φ = 576599040.

The previous prime is 865471193. The next prime is 865471249. The reversal of 865471221 is 122174568.

865471221 is a `hidden beast` number, since 86 + 547 + 12 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (865471193) and next prime (865471249).

It can be written as a sum of positive squares in 2 ways, for example, as 130302225 + 735168996 = 11415^2 + 27114^2 .

It is not a de Polignac number, because 865471221 - 2⁹ = 865470709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865478221) 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, 17100 + ... + 44981.

It is an arithmetic number, because the mean of its divisors is an integer number (104246025).

Almost surely, 2^865471221 is an apocalyptic number.

It is an amenable number.

865471221 is a deficient number, since it is larger than the sum of its proper divisors (385481079).

865471221 is a wasteful number, since it uses less digits than its factorization.

865471221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63636 (or 63633 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 865471221 is about 29418.8922463100. The cubic root of 865471221 is about 952.9809305862.

The spelling of 865471221 in words is "eight hundred sixty-five million, four hundred seventy-one thousand, two hundred twenty-one".