77968889 has 2 divisors, whose sum is σ = 77968890. Its totient is φ = 77968888.

The previous prime is 77968861. The next prime is 77968903. The reversal of 77968889 is 98886977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75550864 + 2418025 = 8692^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 77968889 - 2¹² = 77964793 is a prime.

It is not a weakly prime, because it can be changed into another prime (77968859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38984444 + 38984445.

It is an arithmetic number, because the mean of its divisors is an integer number (38984445).

Almost surely, 2^77968889 is an apocalyptic number.

It is an amenable number.

77968889 is a deficient number, since it is larger than the sum of its proper divisors (1).

77968889 is an equidigital number, since it uses as much as digits as its factorization.

77968889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12192768, while the sum is 62.

The square root of 77968889 is about 8829.9993771234. Note that the first 3 decimals coincide. The cubic root of 77968889 is about 427.2090543402.

The spelling of 77968889 in words is "seventy-seven million, nine hundred sixty-eight thousand, eight hundred eighty-nine".