77868191999 has 4 divisors (see below), whose sum is σ = 83858052936. Its totient is φ = 71878331064.

The previous prime is 77868191981. The next prime is 77868192013. The reversal of 77868191999 is 99919186877.

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

It is a cyclic number.

It is not a de Polignac number, because 77868191999 - 2²⁰ = 77867143423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77868191969) 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, 2994930449 + ... + 2994930474.

It is an arithmetic number, because the mean of its divisors is an integer number (20964513234).

Almost surely, 2^77868191999 is an apocalyptic number.

77868191999 is a deficient number, since it is larger than the sum of its proper divisors (5989860937).

77868191999 is a wasteful number, since it uses less digits than its factorization.

77868191999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5989860936.

The product of its digits is 123451776, while the sum is 74.

The spelling of 77868191999 in words is "seventy-seven billion, eight hundred sixty-eight million, one hundred ninety-one thousand, nine hundred ninety-nine".