78394819 has 2 divisors, whose sum is σ = 78394820. Its totient is φ = 78394818.

The previous prime is 78394759. The next prime is 78394843. The reversal of 78394819 is 91849387.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78394819 - 2¹⁵ = 78362051 is a prime.

It is a super-2 number, since 2×78394819² = 12291495292085522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78394889) 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, 39197409 + 39197410.

It is an arithmetic number, because the mean of its divisors is an integer number (39197410).

Almost surely, 2^78394819 is an apocalyptic number.

78394819 is a deficient number, since it is larger than the sum of its proper divisors (1).

78394819 is an equidigital number, since it uses as much as digits as its factorization.

78394819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 49.

The square root of 78394819 is about 8854.0848764850. The cubic root of 78394819 is about 427.9855641185.

The spelling of 78394819 in words is "seventy-eight million, three hundred ninety-four thousand, eight hundred nineteen".