78398069 has 2 divisors, whose sum is σ = 78398070. Its totient is φ = 78398068.

The previous prime is 78398059. The next prime is 78398071. The reversal of 78398069 is 96089387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74615044 + 3783025 = 8638^2 + 1945^2 .

It is an emirp because it is prime and its reverse (96089387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78398069 - 2¹⁶ = 78332533 is a prime.

It is a super-2 number, since 2×78398069² = 12292514445857522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 78398071, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78398059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39199034 + 39199035.

It is an arithmetic number, because the mean of its divisors is an integer number (39199035).

Almost surely, 2^78398069 is an apocalyptic number.

It is an amenable number.

78398069 is a deficient number, since it is larger than the sum of its proper divisors (1).

78398069 is an equidigital number, since it uses as much as digits as its factorization.

78398069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 50.

The square root of 78398069 is about 8854.2684056900. The cubic root of 78398069 is about 427.9914783437.

The spelling of 78398069 in words is "seventy-eight million, three hundred ninety-eight thousand, sixty-nine".