861026999 has 24 divisors (see below), whose sum is σ = 1054136160. Its totient is φ = 686555136.

The previous prime is 861026989. The next prime is 861027001. The reversal of 861026999 is 999620168.

It is not a de Polignac number, because 861026999 - 2²⁰ = 859978423 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861026989) 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 23 ways as a sum of consecutive naturals, for example, 1119287 + ... + 1120055.

It is an arithmetic number, because the mean of its divisors is an integer number (43922340).

Almost surely, 2^861026999 is an apocalyptic number.

861026999 is a deficient number, since it is larger than the sum of its proper divisors (193109161).

861026999 is an equidigital number, since it uses as much as digits as its factorization.

861026999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987 (or 890 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 861026999 is about 29343.2615603651. The cubic root of 861026999 is about 951.3469348075.

The spelling of 861026999 in words is "eight hundred sixty-one million, twenty-six thousand, nine hundred ninety-nine".