77845 has 4 divisors (see below), whose sum is σ = 93420. Its totient is φ = 62272.

The previous prime is 77839. The next prime is 77849. The reversal of 77845 is 54877.

It is a happy number.

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 28561 + 49284 = 169^2 + 222^2 .

It is a cyclic number.

It is not a de Polignac number, because 77845 - 2⁵ = 77813 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 congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 77845.

It is not an unprimeable number, because it can be changed into a prime (77849) 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, 7780 + ... + 7789.

It is an arithmetic number, because the mean of its divisors is an integer number (23355).

2⁷⁷⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

77845 is a deficient number, since it is larger than the sum of its proper divisors (15575).

77845 is a wasteful number, since it uses less digits than its factorization.

77845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15574.

The product of its digits is 7840, while the sum is 31.

The square root of 77845 is about 279.0071683667. The cubic root of 77845 is about 42.6982662504.

The spelling of 77845 in words is "seventy-seven thousand, eight hundred forty-five".