77851 has 4 divisors (see below), whose sum is σ = 78592. Its totient is φ = 77112.

The previous prime is 77849. The next prime is 77863. The reversal of 77851 is 15877.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 77851 - 2¹ = 77849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77801) 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 3 ways as a sum of consecutive naturals, for example, 180 + ... + 433.

It is an arithmetic number, because the mean of its divisors is an integer number (19648).

2⁷⁷⁸⁵¹ is an apocalyptic number.

77851 is a deficient number, since it is larger than the sum of its proper divisors (741).

77851 is a wasteful number, since it uses less digits than its factorization.

77851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740.

The product of its digits is 1960, while the sum is 28.

The square root of 77851 is about 279.0179205714. The cubic root of 77851 is about 42.6993632295.

The spelling of 77851 in words is "seventy-seven thousand, eight hundred fifty-one".