861638858 has 4 divisors (see below), whose sum is σ = 1292458290. Its totient is φ = 430819428.

The previous prime is 861638851. The next prime is 861638867. The reversal of 861638858 is 858836168.

861638858 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 799023289 + 62615569 = 28267^2 + 7913^2 .

It is not an unprimeable number, because it can be changed into a prime (861638851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 215409713 + ... + 215409716.

Almost surely, 2^861638858 is an apocalyptic number.

861638858 is a deficient number, since it is larger than the sum of its proper divisors (430819432).

861638858 is a wasteful number, since it uses less digits than its factorization.

861638858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430819431.

The product of its digits is 2211840, while the sum is 53.

The square root of 861638858 is about 29353.6855948278. The cubic root of 861638858 is about 951.5722286943.

It can be divided in two parts, 8616 and 38858, that added together give a palindrome (47474).

The spelling of 861638858 in words is "eight hundred sixty-one million, six hundred thirty-eight thousand, eight hundred fifty-eight".