78115489 has 2 divisors, whose sum is σ = 78115490. Its totient is φ = 78115488.

The previous prime is 78115487. The next prime is 78115511. The reversal of 78115489 is 98451187.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42510400 + 35605089 = 6520^2 + 5967^2 .

It is a cyclic number.

It is not a de Polignac number, because 78115489 - 2¹ = 78115487 is a prime.

It is a super-2 number, since 2×78115489² = 12204059243418242, which contains 22 as substring.

Together with 78115487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78115483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39057744 + 39057745.

It is an arithmetic number, because the mean of its divisors is an integer number (39057745).

Almost surely, 2^78115489 is an apocalyptic number.

It is an amenable number.

78115489 is a deficient number, since it is larger than the sum of its proper divisors (1).

78115489 is an equidigital number, since it uses as much as digits as its factorization.

78115489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80640, while the sum is 43.

The square root of 78115489 is about 8838.2967250483. The cubic root of 78115489 is about 427.4766381452.

The spelling of 78115489 in words is "seventy-eight million, one hundred fifteen thousand, four hundred eighty-nine".