91861 has 8 divisors (see below), whose sum is σ = 114624. Its totient is φ = 71520.

The previous prime is 91841. The next prime is 91867. The reversal of 91861 is 16819.

91861 = T₅ + T₆ + ... + T₈₁.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91861 - 2⁷ = 91733 is a prime.

It is a Duffinian number.

91861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520 + ... + 673.

It is an arithmetic number, because the mean of its divisors is an integer number (14328).

2⁹¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

91861 is a deficient number, since it is larger than the sum of its proper divisors (22763).

91861 is a wasteful number, since it uses less digits than its factorization.

91861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211.

The product of its digits is 432, while the sum is 25.

The square root of 91861 is about 303.0857964339. The cubic root of 91861 is about 45.1208275442.

It can be divided in two parts, 918 and 61, that added together give a palindrome (979).

The spelling of 91861 in words is "ninety-one thousand, eight hundred sixty-one".