77878771523 has 4 divisors (see below), whose sum is σ = 89004310320. Its totient is φ = 66753232728.

The previous prime is 77878771511. The next prime is 77878771559. The reversal of 77878771523 is 32517787877.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 77878771523 - 2²² = 77874577219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77878771573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5562769388 + ... + 5562769401.

It is an arithmetic number, because the mean of its divisors is an integer number (22251077580).

Almost surely, 2^77878771523 is an apocalyptic number.

77878771523 is a deficient number, since it is larger than the sum of its proper divisors (11125538797).

77878771523 is a wasteful number, since it uses less digits than its factorization.

77878771523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11125538796.

The product of its digits is 32269440, while the sum is 62.

The spelling of 77878771523 in words is "seventy-seven billion, eight hundred seventy-eight million, seven hundred seventy-one thousand, five hundred twenty-three".