201861 has 12 divisors (see below), whose sum is σ = 318240. Its totient is φ = 122280.

The previous prime is 201847. The next prime is 201881. The reversal of 201861 is 168102.

It is not a de Polignac number, because 201861 - 2⁵ = 201829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 921 + ... + 1118.

It is an arithmetic number, because the mean of its divisors is an integer number (26520).

2²⁰¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

201861 is a deficient number, since it is larger than the sum of its proper divisors (116379).

201861 is a wasteful number, since it uses less digits than its factorization.

201861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2056 (or 2053 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 201861 is about 449.2894390034. The cubic root of 201861 is about 58.6611816210.

Adding to 201861 its reverse (168102), we get a palindrome (369963).

It can be divided in two parts, 20 and 1861, that added together give a palindrome (1881).

The spelling of 201861 in words is "two hundred one thousand, eight hundred sixty-one".