77828 has 6 divisors (see below), whose sum is σ = 136206. Its totient is φ = 38912.

The previous prime is 77813. The next prime is 77839. The reversal of 77828 is 82877.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 73984 + 3844 = 272^2 + 62^2 .

It is a junction number, because it is equal to n+sod(n) for n = 77794 and 77803.

It is an unprimeable number.

77828 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9725 + ... + 9732.

It is an arithmetic number, because the mean of its divisors is an integer number (22701).

2⁷⁷⁸²⁸ is an apocalyptic number.

It is an amenable number.

77828 is a deficient number, since it is larger than the sum of its proper divisors (58378).

77828 is a wasteful number, since it uses less digits than its factorization.

77828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19461 (or 19459 counting only the distinct ones).

The product of its digits is 6272, while the sum is 32.

The square root of 77828 is about 278.9767015362. The cubic root of 77828 is about 42.6951578368.

Adding to 77828 its product of digits (6272), we get a square (84100 = 290²).

The spelling of 77828 in words is "seventy-seven thousand, eight hundred twenty-eight".