78321239 has 2 divisors, whose sum is σ = 78321240. Its totient is φ = 78321238.

The previous prime is 78321197. The next prime is 78321247. The reversal of 78321239 is 93212387.

It is a strong prime.

It is an emirp because it is prime and its reverse (93212387) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78321239 is a prime.

It is a super-2 number, since 2×78321239² = 12268432956990242, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 78321199 and 78321208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78321259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39160619 + 39160620.

It is an arithmetic number, because the mean of its divisors is an integer number (39160620).

Almost surely, 2^78321239 is an apocalyptic number.

78321239 is a deficient number, since it is larger than the sum of its proper divisors (1).

78321239 is an equidigital number, since it uses as much as digits as its factorization.

78321239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 35.

The square root of 78321239 is about 8849.9287567754. The cubic root of 78321239 is about 427.8516222938.

It can be divided in two parts, 783 and 21239, that added together give a palindrome (22022).

The spelling of 78321239 in words is "seventy-eight million, three hundred twenty-one thousand, two hundred thirty-nine".