77856805 has 16 divisors (see below), whose sum is σ = 100873584. Its totient is φ = 57346560.

The previous prime is 77856799. The next prime is 77856809. The reversal of 77856805 is 50865877.

It can be written as a sum of positive squares in 8 ways, for example, as 1014049 + 76842756 = 1007^2 + 8766^2 .

It is not a de Polignac number, because 77856805 - 2⁹ = 77856293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77856809) 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 15 ways as a sum of consecutive naturals, for example, 28395 + ... + 31015.

It is an arithmetic number, because the mean of its divisors is an integer number (6304599).

Almost surely, 2^77856805 is an apocalyptic number.

It is an amenable number.

77856805 is a deficient number, since it is larger than the sum of its proper divisors (23016779).

77856805 is a wasteful number, since it uses less digits than its factorization.

77856805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3096.

The product of its (nonzero) digits is 470400, while the sum is 46.

The square root of 77856805 is about 8823.6503217206. The cubic root of 77856805 is about 427.0042450313.

The spelling of 77856805 in words is "seventy-seven million, eight hundred fifty-six thousand, eight hundred five".