77138778 has 16 divisors (see below), whose sum is σ = 154381536. Its totient is φ = 25695600.

The previous prime is 77138777. The next prime is 77138791. The reversal of 77138778 is 87783177.

It is not an unprimeable number, because it can be changed into a prime (77138771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8025 + ... + 14787.

It is an arithmetic number, because the mean of its divisors is an integer number (9648846).

Almost surely, 2^77138778 is an apocalyptic number.

77138778 is an abundant number, since it is smaller than the sum of its proper divisors (77242758).

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

77138778 is a wasteful number, since it uses less digits than its factorization.

77138778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8669.

The product of its digits is 460992, while the sum is 48.

The square root of 77138778 is about 8782.8684380446. The cubic root of 77138778 is about 425.6875201899.

The spelling of 77138778 in words is "seventy-seven million, one hundred thirty-eight thousand, seven hundred seventy-eight".