78444389 has 2 divisors, whose sum is σ = 78444390. Its totient is φ = 78444388.

The previous prime is 78444371. The next prime is 78444433. The reversal of 78444389 is 98344487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78021889 + 422500 = 8833^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 78444389 - 2²⁴ = 61667173 is a prime.

It is a super-3 number, since 3×78444389³ (a number of 25 digits) contains 333 as substring.

It is a Sophie Germain prime.

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 (78444319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39222194 + 39222195.

It is an arithmetic number, because the mean of its divisors is an integer number (39222195).

Almost surely, 2^78444389 is an apocalyptic number.

It is an amenable number.

78444389 is a deficient number, since it is larger than the sum of its proper divisors (1).

78444389 is an equidigital number, since it uses as much as digits as its factorization.

78444389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 774144, while the sum is 47.

The square root of 78444389 is about 8856.8837070383. The cubic root of 78444389 is about 428.0757519425.

The spelling of 78444389 in words is "seventy-eight million, four hundred forty-four thousand, three hundred eighty-nine".