861322309 has 2 divisors, whose sum is σ = 861322310. Its totient is φ = 861322308.

The previous prime is 861322303. The next prime is 861322327. The reversal of 861322309 is 903223168.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 770062500 + 91259809 = 27750^2 + 9553^2 .

It is a cyclic number.

It is not a de Polignac number, because 861322309 - 2⁵ = 861322277 is a prime.

It is a super-2 number, since 2×861322309² = 1483752239962182962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861322303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430661154 + 430661155.

It is an arithmetic number, because the mean of its divisors is an integer number (430661155).

Almost surely, 2^861322309 is an apocalyptic number.

It is an amenable number.

861322309 is a deficient number, since it is larger than the sum of its proper divisors (1).

861322309 is an equidigital number, since it uses as much as digits as its factorization.

861322309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 861322309 is about 29348.2931190214. The cubic root of 861322309 is about 951.4556848432.

The spelling of 861322309 in words is "eight hundred sixty-one million, three hundred twenty-two thousand, three hundred nine".