65861 has 4 divisors (see below), whose sum is σ = 66912. Its totient is φ = 64812.

The previous prime is 65851. The next prime is 65867. The reversal of 65861 is 16856.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 65861 - 2¹⁴ = 49477 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 65861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 425 + ... + 558.

It is an arithmetic number, because the mean of its divisors is an integer number (16728).

2⁶⁵⁸⁶¹ is an apocalyptic number.

It is an amenable number.

65861 is a deficient number, since it is larger than the sum of its proper divisors (1051).

65861 is an equidigital number, since it uses as much as digits as its factorization.

65861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050.

The product of its digits is 1440, while the sum is 26.

The square root of 65861 is about 256.6339806027. The cubic root of 65861 is about 40.3840099450.

The spelling of 65861 in words is "sixty-five thousand, eight hundred sixty-one".