78528889 has 2 divisors, whose sum is σ = 78528890. Its totient is φ = 78528888.

The previous prime is 78528887. The next prime is 78528893. The reversal of 78528889 is 98882587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70644025 + 7884864 = 8405^2 + 2808^2 .

It is an emirp because it is prime and its reverse (98882587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78528889 - 2¹ = 78528887 is a prime.

It is a super-4 number, since 4×78528889⁴ (a number of 33 digits) contains 4444 as substring.

Together with 78528887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78528887) 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, 39264444 + 39264445.

It is an arithmetic number, because the mean of its divisors is an integer number (39264445).

Almost surely, 2^78528889 is an apocalyptic number.

It is an amenable number.

78528889 is a deficient number, since it is larger than the sum of its proper divisors (1).

78528889 is an equidigital number, since it uses as much as digits as its factorization.

78528889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2580480, while the sum is 55.

The square root of 78528889 is about 8861.6527239562. The cubic root of 78528889 is about 428.2294039798.

The spelling of 78528889 in words is "seventy-eight million, five hundred twenty-eight thousand, eight hundred eighty-nine".