78885649 has 2 divisors, whose sum is σ = 78885650. Its totient is φ = 78885648.

The previous prime is 78885647. The next prime is 78885671. The reversal of 78885649 is 94658887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70224400 + 8661249 = 8380^2 + 2943^2 .

It is a cyclic number.

It is not a de Polignac number, because 78885649 - 2¹ = 78885647 is a prime.

Together with 78885647, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 78885649.

It is not a weakly prime, because it can be changed into another prime (78885647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39442824 + 39442825.

It is an arithmetic number, because the mean of its divisors is an integer number (39442825).

Almost surely, 2^78885649 is an apocalyptic number.

It is an amenable number.

78885649 is a deficient number, since it is larger than the sum of its proper divisors (1).

78885649 is an equidigital number, since it uses as much as digits as its factorization.

78885649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3870720, while the sum is 55.

The square root of 78885649 is about 8881.7593414818. The cubic root of 78885649 is about 428.8769123965.

The spelling of 78885649 in words is "seventy-eight million, eight hundred eighty-five thousand, six hundred forty-nine".