77778320 has 20 divisors (see below), whose sum is σ = 180834780. Its totient is φ = 31111296.

The previous prime is 77778313. The next prime is 77778331. The reversal of 77778320 is 2387777.

It can be written as a sum of positive squares in 2 ways, for example, as 49730704 + 28047616 = 7052^2 + 5296^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 486035 + ... + 486194.

It is an arithmetic number, because the mean of its divisors is an integer number (9041739).

Almost surely, 2^77778320 is an apocalyptic number.

It is an amenable number.

77778320 is an abundant number, since it is smaller than the sum of its proper divisors (103056460).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77778320 is a wasteful number, since it uses less digits than its factorization.

77778320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972242 (or 972236 counting only the distinct ones).

The product of its (nonzero) digits is 115248, while the sum is 41.

The square root of 77778320 is about 8819.2017779389. The cubic root of 77778320 is about 426.8607136009.

It can be divided in two parts, 777 and 78320, that added together give a palindrome (79097).

The spelling of 77778320 in words is "seventy-seven million, seven hundred seventy-eight thousand, three hundred twenty".