78189493 has 2 divisors, whose sum is σ = 78189494. Its totient is φ = 78189492.

The previous prime is 78189457. The next prime is 78189521. The reversal of 78189493 is 39498187.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72029169 + 6160324 = 8487^2 + 2482^2 .

It is an emirp because it is prime and its reverse (39498187) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78189493 is a prime.

It is a super-2 number, since 2×78189493² = 12227193631194098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78189593) 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, 39094746 + 39094747.

It is an arithmetic number, because the mean of its divisors is an integer number (39094747).

Almost surely, 2^78189493 is an apocalyptic number.

It is an amenable number.

78189493 is a deficient number, since it is larger than the sum of its proper divisors (1).

78189493 is an equidigital number, since it uses as much as digits as its factorization.

78189493 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 78189493 is about 8842.4822872313. The cubic root of 78189493 is about 427.6115878921.

The spelling of 78189493 in words is "seventy-eight million, one hundred eighty-nine thousand, four hundred ninety-three".