861861785 has 8 divisors (see below), whose sum is σ = 1044474696. Its totient is φ = 682662400.

The previous prime is 861861769. The next prime is 861861811. The reversal of 861861785 is 587168168.

It can be written as a sum of positive squares in 4 ways, for example, as 567773584 + 294088201 = 23828^2 + 17149^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 861861785 - 2⁴ = 861861769 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 852824 + ... + 853833.

It is an arithmetic number, because the mean of its divisors is an integer number (130559337).

Almost surely, 2^861861785 is an apocalyptic number.

It is an amenable number.

861861785 is a deficient number, since it is larger than the sum of its proper divisors (182612911).

861861785 is a wasteful number, since it uses less digits than its factorization.

861861785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706763.

The product of its digits is 645120, while the sum is 50.

The square root of 861861785 is about 29357.4826066541. The cubic root of 861861785 is about 951.6542866038.

The spelling of 861861785 in words is "eight hundred sixty-one million, eight hundred sixty-one thousand, seven hundred eighty-five".