78578239 has 2 divisors, whose sum is σ = 78578240. Its totient is φ = 78578238.

The previous prime is 78578237. The next prime is 78578249. The reversal of 78578239 is 93287587.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78578239 - 2¹ = 78578237 is a prime.

It is a super-2 number, since 2×78578239² = 12349079288682242, which contains 22 as substring.

Together with 78578237, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 78578192 and 78578201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78578237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39289119 + 39289120.

It is an arithmetic number, because the mean of its divisors is an integer number (39289120).

Almost surely, 2^78578239 is an apocalyptic number.

78578239 is a deficient number, since it is larger than the sum of its proper divisors (1).

78578239 is an equidigital number, since it uses as much as digits as its factorization.

78578239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 49.

The square root of 78578239 is about 8864.4367559366. The cubic root of 78578239 is about 428.3190894276.

The spelling of 78578239 in words is "seventy-eight million, five hundred seventy-eight thousand, two hundred thirty-nine".