77881777 has 4 divisors (see below), whose sum is σ = 82463076. Its totient is φ = 73300480.

The previous prime is 77881759. The next prime is 77881789. The reversal of 77881777 is 77718877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77718877 = 379 ⋅205063.

It can be written as a sum of positive squares in 2 ways, for example, as 72573361 + 5308416 = 8519^2 + 2304^2 .

It is a cyclic number.

It is not a de Polignac number, because 77881777 - 2⁷ = 77881649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77881717) by changing a digit.

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, 2290624 + ... + 2290657.

It is an arithmetic number, because the mean of its divisors is an integer number (20615769).

Almost surely, 2^77881777 is an apocalyptic number.

It is an amenable number.

77881777 is a deficient number, since it is larger than the sum of its proper divisors (4581299).

77881777 is a wasteful number, since it uses less digits than its factorization.

77881777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4581298.

The product of its digits is 1075648, while the sum is 52.

The square root of 77881777 is about 8825.0652688805. The cubic root of 77881777 is about 427.0498929793.

The spelling of 77881777 in words is "seventy-seven million, eight hundred eighty-one thousand, seven hundred seventy-seven".