77899889 has 2 divisors, whose sum is σ = 77899890. Its totient is φ = 77899888.

The previous prime is 77899859. The next prime is 77899891. The reversal of 77899889 is 98899877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77299264 + 600625 = 8792^2 + 775^2 .

It is an emirp because it is prime and its reverse (98899877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77899889 - 2²⁴ = 61122673 is a prime.

Together with 77899891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77899849) 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 as a sum of consecutive naturals, namely, 38949944 + 38949945.

It is an arithmetic number, because the mean of its divisors is an integer number (38949945).

Almost surely, 2^77899889 is an apocalyptic number.

It is an amenable number.

77899889 is a deficient number, since it is larger than the sum of its proper divisors (1).

77899889 is an equidigital number, since it uses as much as digits as its factorization.

77899889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18289152, while the sum is 65.

The square root of 77899889 is about 8826.0913772745. The cubic root of 77899889 is about 427.0829949810.

The spelling of 77899889 in words is "seventy-seven million, eight hundred ninety-nine thousand, eight hundred eighty-nine".