77639999 has 2 divisors, whose sum is σ = 77640000. Its totient is φ = 77639998.

The previous prime is 77639977. The next prime is 77640001. The reversal of 77639999 is 99993677.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77639999 - 2¹² = 77635903 is a prime.

Together with 77640001, it forms a pair of twin primes.

It is a Chen prime.

77639999 is a modest number, since divided by 9999 gives 7763 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77639959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38819999 + 38820000.

It is an arithmetic number, because the mean of its divisors is an integer number (38820000).

Almost surely, 2^77639999 is an apocalyptic number.

77639999 is a deficient number, since it is larger than the sum of its proper divisors (1).

77639999 is an equidigital number, since it uses as much as digits as its factorization.

77639999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5786802, while the sum is 59.

The square root of 77639999 is about 8811.3562520193. The cubic root of 77639999 is about 426.6075203522.

The spelling of 77639999 in words is "seventy-seven million, six hundred thirty-nine thousand, nine hundred ninety-nine".