16861 has 4 divisors (see below), whose sum is σ = 18172. Its totient is φ = 15552.

The previous prime is 16843. The next prime is 16871.

16861 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11236 + 5625 = 106^2 + 75^2 .

It is a 5-Lehmer number, since φ(16861) divides (16861-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 16861 - 2⁵ = 16829 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 636 + ... + 661.

It is an arithmetic number, because the mean of its divisors is an integer number (4543).

2¹⁶⁸⁶¹ is an apocalyptic number.

It is an amenable number.

16861 is a deficient number, since it is larger than the sum of its proper divisors (1311).

16861 is a wasteful number, since it uses less digits than its factorization.

16861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1310.

The product of its digits is 288, while the sum is 22.

The square root of 16861 is about 129.8499133615. The cubic root of 16861 is about 25.6425440041.

The spelling of 16861 in words is "sixteen thousand, eight hundred sixty-one".