861089731 has 4 divisors (see below), whose sum is σ = 866792464. Its totient is φ = 855387000.

The previous prime is 861089711. The next prime is 861089737. The reversal of 861089731 is 137980168.

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 861089731 - 2⁵ = 861089699 is a prime.

It is a super-2 number, since 2×861089731² = 1482951049667304722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861089737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2851140 + ... + 2851441.

It is an arithmetic number, because the mean of its divisors is an integer number (216698116).

Almost surely, 2^861089731 is an apocalyptic number.

861089731 is a deficient number, since it is larger than the sum of its proper divisors (5702733).

861089731 is a wasteful number, since it uses less digits than its factorization.

861089731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5702732.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 861089731 is about 29344.3304745568. The cubic root of 861089731 is about 951.3700383984.

The spelling of 861089731 in words is "eight hundred sixty-one million, eighty-nine thousand, seven hundred thirty-one".