81877 has 4 divisors (see below), whose sum is σ = 83916. Its totient is φ = 79840.

The previous prime is 81869. The next prime is 81883. The reversal of 81877 is 77818.

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 2916 + 78961 = 54^2 + 281^2 .

It is a cyclic number.

It is not a de Polignac number, because 81877 - 2³ = 81869 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81817) 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, 958 + ... + 1039.

It is an arithmetic number, because the mean of its divisors is an integer number (20979).

2⁸¹⁸⁷⁷ is an apocalyptic number.

It is an amenable number.

81877 is a deficient number, since it is larger than the sum of its proper divisors (2039).

81877 is a wasteful number, since it uses less digits than its factorization.

81877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2038.

The product of its digits is 3136, while the sum is 31.

The square root of 81877 is about 286.1415733514. The cubic root of 81877 is about 43.4230815800.

The spelling of 81877 in words is "eighty-one thousand, eight hundred seventy-seven".