77820885 has 32 divisors (see below), whose sum is σ = 138948480. Its totient is φ = 41324544.

The previous prime is 77820859. The next prime is 77820887. The reversal of 77820885 is 58802877.

It is a happy number.

It is not a de Polignac number, because 77820885 - 2⁸ = 77820629 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 77820885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77820887) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33574 + ... + 35816.

It is an arithmetic number, because the mean of its divisors is an integer number (4342140).

Almost surely, 2^77820885 is an apocalyptic number.

It is an amenable number.

77820885 is a deficient number, since it is larger than the sum of its proper divisors (61127595).

77820885 is a wasteful number, since it uses less digits than its factorization.

77820885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2514 (or 2508 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 45.

The square root of 77820885 is about 8821.6146481242. The cubic root of 77820885 is about 426.9385673988.

The spelling of 77820885 in words is "seventy-seven million, eight hundred twenty thousand, eight hundred eighty-five".