78512689 has 2 divisors, whose sum is σ = 78512690. Its totient is φ = 78512688.

The previous prime is 78512683. The next prime is 78512737. The reversal of 78512689 is 98621587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58262689 + 20250000 = 7633^2 + 4500^2 .

It is a cyclic number.

It is not a de Polignac number, because 78512689 - 2⁷ = 78512561 is a prime.

It is not a weakly prime, because it can be changed into another prime (78512683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39256344 + 39256345.

It is an arithmetic number, because the mean of its divisors is an integer number (39256345).

Almost surely, 2^78512689 is an apocalyptic number.

It is an amenable number.

78512689 is a deficient number, since it is larger than the sum of its proper divisors (1).

78512689 is an equidigital number, since it uses as much as digits as its factorization.

78512689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 46.

The square root of 78512689 is about 8860.7386260966. The cubic root of 78512689 is about 428.1999549726.

The spelling of 78512689 in words is "seventy-eight million, five hundred twelve thousand, six hundred eighty-nine".