78238819 has 2 divisors, whose sum is σ = 78238820. Its totient is φ = 78238818.

The previous prime is 78238817. The next prime is 78238843. The reversal of 78238819 is 91883287.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78238819 - 2¹ = 78238817 is a prime.

It is a super-2 number, since 2×78238819² = 12242625597029522, which contains 22 as substring.

Together with 78238817, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78238817) 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, 39119409 + 39119410.

It is an arithmetic number, because the mean of its divisors is an integer number (39119410).

Almost surely, 2^78238819 is an apocalyptic number.

78238819 is a deficient number, since it is larger than the sum of its proper divisors (1).

78238819 is an equidigital number, since it uses as much as digits as its factorization.

78238819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 46.

The square root of 78238819 is about 8845.2709964138. The cubic root of 78238819 is about 427.7014888687.

It can be divided in two parts, 782 and 38819, that added together give a square (39601 = 199²).

The spelling of 78238819 in words is "seventy-eight million, two hundred thirty-eight thousand, eight hundred nineteen".