77861 has 8 divisors (see below), whose sum is σ = 91200. Its totient is φ = 66444.

The previous prime is 77849. The next prime is 77863. The reversal of 77861 is 16877.

It is not a de Polignac number, because 77861 - 2⁶ = 77797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77863) 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, 230 + ... + 456.

It is an arithmetic number, because the mean of its divisors is an integer number (11400).

2⁷⁷⁸⁶¹ is an apocalyptic number.

It is an amenable number.

77861 is a deficient number, since it is larger than the sum of its proper divisors (13339).

77861 is an equidigital number, since it uses as much as digits as its factorization.

77861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248 (or 234 counting only the distinct ones).

The product of its digits is 2352, while the sum is 29.

The square root of 77861 is about 279.0358399919. The cubic root of 77861 is about 42.7011914028.

The spelling of 77861 in words is "seventy-seven thousand, eight hundred sixty-one".