78625649 has 2 divisors, whose sum is σ = 78625650. Its totient is φ = 78625648.

The previous prime is 78625643. The next prime is 78625669. The reversal of 78625649 is 94652687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66129424 + 12496225 = 8132^2 + 3535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78625649 is a prime.

It is not a weakly prime, because it can be changed into another prime (78625643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39312824 + 39312825.

It is an arithmetic number, because the mean of its divisors is an integer number (39312825).

Almost surely, 2^78625649 is an apocalyptic number.

It is an amenable number.

78625649 is a deficient number, since it is larger than the sum of its proper divisors (1).

78625649 is an equidigital number, since it uses as much as digits as its factorization.

78625649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 47.

The square root of 78625649 is about 8867.1105214720. The cubic root of 78625649 is about 428.4052138885.

The spelling of 78625649 in words is "seventy-eight million, six hundred twenty-five thousand, six hundred forty-nine".