79861 has 2 divisors, whose sum is σ = 79862. Its totient is φ = 79860.

The previous prime is 79847. The next prime is 79867. The reversal of 79861 is 16897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78961 + 900 = 281^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 79861 - 2⁵ = 79829 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39930 + 39931.

It is an arithmetic number, because the mean of its divisors is an integer number (39931).

2⁷⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

79861 is a deficient number, since it is larger than the sum of its proper divisors (1).

79861 is an equidigital number, since it uses as much as digits as its factorization.

79861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 31.

The square root of 79861 is about 282.5968860409. The cubic root of 79861 is about 43.0637237981.

The spelling of 79861 in words is "seventy-nine thousand, eight hundred sixty-one".