861779317 has 12 divisors (see below), whose sum is σ = 1061448300. Its totient is φ = 695216256.

The previous prime is 861779299. The next prime is 861779329. The reversal of 861779317 is 713977168.

It can be written as a sum of positive squares in 2 ways, for example, as 657460881 + 204318436 = 25641^2 + 14294^2 .

It is not a de Polignac number, because 861779317 - 2¹⁹ = 861255029 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861779117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 516442 + ... + 518107.

It is an arithmetic number, because the mean of its divisors is an integer number (88454025).

Almost surely, 2^861779317 is an apocalyptic number.

It is an amenable number.

861779317 is a deficient number, since it is larger than the sum of its proper divisors (199668983).

861779317 is a wasteful number, since it uses less digits than its factorization.

861779317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034580 (or 1034573 counting only the distinct ones).

The product of its digits is 444528, while the sum is 49.

The square root of 861779317 is about 29356.0780248316. The cubic root of 861779317 is about 951.6239323443.

The spelling of 861779317 in words is "eight hundred sixty-one million, seven hundred seventy-nine thousand, three hundred seventeen".