861081999 has 8 divisors (see below), whose sum is σ = 1151732400. Its totient is φ = 572243136.

The previous prime is 861081997. The next prime is 861082003. The reversal of 861081999 is 999180168.

It is a happy number.

861081999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 861081999 - 2¹ = 861081997 is a prime.

It is a super-3 number, since 3×861081999³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861081997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 451774 + ... + 453675.

It is an arithmetic number, because the mean of its divisors is an integer number (143966550).

Almost surely, 2^861081999 is an apocalyptic number.

861081999 is a deficient number, since it is larger than the sum of its proper divisors (290650401).

861081999 is a wasteful number, since it uses less digits than its factorization.

861081999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905769.

The product of its (nonzero) digits is 279936, while the sum is 51.

The square root of 861081999 is about 29344.1987281984. The cubic root of 861081999 is about 951.3671908379.

It can be divided in two parts, 8610 and 81999, that added together give a palindrome (90609).

The spelling of 861081999 in words is "eight hundred sixty-one million, eighty-one thousand, nine hundred ninety-nine".