77985 has 12 divisors (see below), whose sum is σ = 135252. Its totient is φ = 41568.

The previous prime is 77983. The next prime is 77999. The reversal of 77985 is 58977.

It can be written as a sum of positive squares in 2 ways, for example, as 31329 + 46656 = 177^2 + 216^2 .

It is not a de Polignac number, because 77985 - 2¹ = 77983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 822 + ... + 911.

It is an arithmetic number, because the mean of its divisors is an integer number (11271).

2⁷⁷⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

77985 is a deficient number, since it is larger than the sum of its proper divisors (57267).

77985 is a wasteful number, since it uses less digits than its factorization.

77985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1744 (or 1741 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 77985 is about 279.2579452764. The cubic root of 77985 is about 42.7238477576.

The spelling of 77985 in words is "seventy-seven thousand, nine hundred eighty-five".