864781 has 2 divisors, whose sum is σ = 864782. Its totient is φ = 864780.

The previous prime is 864757. The next prime is 864793. The reversal of 864781 is 187468.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 837225 + 27556 = 915^2 + 166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-864781 is a prime.

It is a super-2 number, since 2×864781² = 1495692355922, which contains 22 as substring.

864781 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (864581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432390 + 432391.

It is an arithmetic number, because the mean of its divisors is an integer number (432391).

2⁸⁶⁴⁷⁸¹ is an apocalyptic number.

It is an amenable number.

864781 is a deficient number, since it is larger than the sum of its proper divisors (1).

864781 is an equidigital number, since it uses as much as digits as its factorization.

864781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 34.

The square root of 864781 is about 929.9360193046. The cubic root of 864781 is about 95.2727526286.

The spelling of 864781 in words is "eight hundred sixty-four thousand, seven hundred eighty-one".