78477877809 has 20 divisors (see below), whose sum is σ = 117379574004. Its totient is φ = 52252897824.

The previous prime is 78477877787. The next prime is 78477877823. The reversal of 78477877809 is 90877877487.

78477877809 is a `hidden beast` number, since 7 + 8 + 477 + 8 + 77 + 80 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 30510307584 + 47967570225 = 174672^2 + 219015^2 .

It is not a de Polignac number, because 78477877809 - 2⁸ = 78477877553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78477877109) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 543262 + ... + 672375.

Almost surely, 2^78477877809 is an apocalyptic number.

It is an amenable number.

78477877809 is a deficient number, since it is larger than the sum of its proper divisors (38901696195).

78477877809 is a wasteful number, since it uses less digits than its factorization.

78477877809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1216446 (or 1216437 counting only the distinct ones).

The product of its (nonzero) digits is 309786624, while the sum is 72.

The spelling of 78477877809 in words is "seventy-eight billion, four hundred seventy-seven million, eight hundred seventy-seven thousand, eight hundred nine".