861998173 has 2 divisors, whose sum is σ = 861998174. Its totient is φ = 861998172.

The previous prime is 861998153. The next prime is 861998191. The reversal of 861998173 is 371899168.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 729702169 + 132296004 = 27013^2 + 11502^2 .

It is a cyclic number.

It is not a de Polignac number, because 861998173 - 2¹⁷ = 861867101 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 861998173.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861998143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430999086 + 430999087.

It is an arithmetic number, because the mean of its divisors is an integer number (430999087).

Almost surely, 2^861998173 is an apocalyptic number.

It is an amenable number.

861998173 is a deficient number, since it is larger than the sum of its proper divisors (1).

861998173 is an equidigital number, since it uses as much as digits as its factorization.

861998173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 52.

The square root of 861998173 is about 29359.8053978564. The cubic root of 861998173 is about 951.7044831207.

The spelling of 861998173 in words is "eight hundred sixty-one million, nine hundred ninety-eight thousand, one hundred seventy-three".