861331 has 4 divisors (see below), whose sum is σ = 863200. Its totient is φ = 859464.

The previous prime is 861317. The next prime is 861347. The reversal of 861331 is 133168.

861331 is nontrivially palindromic in base 8.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 861331 - 2⁵ = 861299 is a prime.

It is a super-2 number, since 2×861331² = 1483782183122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 310 + ... + 1348.

It is an arithmetic number, because the mean of its divisors is an integer number (215800).

2⁸⁶¹³³¹ is an apocalyptic number.

861331 is a deficient number, since it is larger than the sum of its proper divisors (1869).

861331 is a wasteful number, since it uses less digits than its factorization.

861331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1868.

The product of its digits is 432, while the sum is 22.

The square root of 861331 is about 928.0791992066. The cubic root of 861331 is about 95.1458884990.

Adding to 861331 its reverse (133168), we get a palindrome (994499).

The spelling of 861331 in words is "eight hundred sixty-one thousand, three hundred thirty-one".