77989819 has 2 divisors, whose sum is σ = 77989820. Its totient is φ = 77989818.

The previous prime is 77989817. The next prime is 77989837. The reversal of 77989819 is 91898977.

It is a weak prime.

It is an emirp because it is prime and its reverse (91898977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77989819 - 2¹ = 77989817 is a prime.

It is a super-2 number, since 2×77989819² = 12164823735305522, which contains 22 as substring.

Together with 77989817, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (77989817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38994909 + 38994910.

It is an arithmetic number, because the mean of its divisors is an integer number (38994910).

Almost surely, 2^77989819 is an apocalyptic number.

77989819 is a deficient number, since it is larger than the sum of its proper divisors (1).

77989819 is an equidigital number, since it uses as much as digits as its factorization.

77989819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 58.

The square root of 77989819 is about 8831.1844618941. The cubic root of 77989819 is about 427.2472776438.

The spelling of 77989819 in words is "seventy-seven million, nine hundred eighty-nine thousand, eight hundred nineteen".