864581 has 2 divisors, whose sum is σ = 864582. Its totient is φ = 864580.

The previous prime is 864551. The next prime is 864583. The reversal of 864581 is 185468.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 828100 + 36481 = 910^2 + 191^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-864581 is a prime.

It is a super-2 number, since 2×864581² = 1495000611122, which contains 22 as substring.

Together with 864583, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 864581.

It is not a weakly prime, because it can be changed into another prime (864583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432290 + 432291.

It is an arithmetic number, because the mean of its divisors is an integer number (432291).

2⁸⁶⁴⁵⁸¹ is an apocalyptic number.

It is an amenable number.

864581 is a deficient number, since it is larger than the sum of its proper divisors (1).

864581 is an equidigital number, since it uses as much as digits as its factorization.

864581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 32.

The square root of 864581 is about 929.8284788067. The cubic root of 864581 is about 95.2654074088.

The spelling of 864581 in words is "eight hundred sixty-four thousand, five hundred eighty-one".