78438389 has 4 divisors (see below), whose sum is σ = 79431360. Its totient is φ = 77445420.

The previous prime is 78438379. The next prime is 78438419. The reversal of 78438389 is 98383487.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78438389 - 2²⁰ = 77389813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78438319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496367 + ... + 496524.

It is an arithmetic number, because the mean of its divisors is an integer number (19857840).

Almost surely, 2^78438389 is an apocalyptic number.

78438389 is a gapful number since it is divisible by the number (79) formed by its first and last digit.

It is an amenable number.

78438389 is a deficient number, since it is larger than the sum of its proper divisors (992971).

78438389 is an equidigital number, since it uses as much as digits as its factorization.

78438389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 992970.

The product of its digits is 1161216, while the sum is 50.

The square root of 78438389 is about 8856.5449809731. The cubic root of 78438389 is about 428.0648375439.

The spelling of 78438389 in words is "seventy-eight million, four hundred thirty-eight thousand, three hundred eighty-nine".