861599 has 2 divisors, whose sum is σ = 861600. Its totient is φ = 861598.

The previous prime is 861589. The next prime is 861613. The reversal of 861599 is 995168.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 861599 - 2¹⁶ = 796063 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430799 + 430800.

It is an arithmetic number, because the mean of its divisors is an integer number (430800).

2⁸⁶¹⁵⁹⁹ is an apocalyptic number.

861599 is a deficient number, since it is larger than the sum of its proper divisors (1).

861599 is an equidigital number, since it uses as much as digits as its factorization.

861599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 38.

The square root of 861599 is about 928.2235722066. The cubic root of 861599 is about 95.1557555745.

It can be divided in two parts, 86159 and 9, that added together give a palindrome (86168).

The spelling of 861599 in words is "eight hundred sixty-one thousand, five hundred ninety-nine".