861997 has 2 divisors, whose sum is σ = 861998. Its totient is φ = 861996.

The previous prime is 861979. The next prime is 862009. The reversal of 861997 is 799168.

861997 is nontrivially palindromic in base 16.

Together with previous prime (861979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 434281 + 427716 = 659^2 + 654^2 .

It is a cyclic number.

It is not a de Polignac number, because 861997 - 2¹⁵ = 829229 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430998 + 430999.

It is an arithmetic number, because the mean of its divisors is an integer number (430999).

2⁸⁶¹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

861997 is a deficient number, since it is larger than the sum of its proper divisors (1).

861997 is an equidigital number, since it uses as much as digits as its factorization.

861997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 40.

The square root of 861997 is about 928.4379354593. The cubic root of 861997 is about 95.1704051430.

The spelling of 861997 in words is "eight hundred sixty-one thousand, nine hundred ninety-seven".