78816889 has 2 divisors, whose sum is σ = 78816890. Its totient is φ = 78816888.

The previous prime is 78816877. The next prime is 78816901. The reversal of 78816889 is 98861887.

It is a balanced prime because it is at equal distance from previous prime (78816877) and next prime (78816901).

It can be written as a sum of positive squares in only one way, i.e., 51724864 + 27092025 = 7192^2 + 5205^2 .

It is a cyclic number.

It is not a de Polignac number, because 78816889 - 2²¹ = 76719737 is a prime.

It is not a weakly prime, because it can be changed into another prime (78816289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39408444 + 39408445.

It is an arithmetic number, because the mean of its divisors is an integer number (39408445).

Almost surely, 2^78816889 is an apocalyptic number.

It is an amenable number.

78816889 is a deficient number, since it is larger than the sum of its proper divisors (1).

78816889 is an equidigital number, since it uses as much as digits as its factorization.

78816889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1548288, while the sum is 55.

The square root of 78816889 is about 8877.8876429024. The cubic root of 78816889 is about 428.7522672123.

The spelling of 78816889 in words is "seventy-eight million, eight hundred sixteen thousand, eight hundred eighty-nine".