78651649 has 2 divisors, whose sum is σ = 78651650. Its totient is φ = 78651648.

The previous prime is 78651637. The next prime is 78651667. The reversal of 78651649 is 94615687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64641600 + 14010049 = 8040^2 + 3743^2 .

It is a cyclic number.

It is not a de Polignac number, because 78651649 - 2⁹ = 78651137 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78651599 and 78651608.

It is not a weakly prime, because it can be changed into another prime (78652649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39325824 + 39325825.

It is an arithmetic number, because the mean of its divisors is an integer number (39325825).

Almost surely, 2^78651649 is an apocalyptic number.

It is an amenable number.

78651649 is a deficient number, since it is larger than the sum of its proper divisors (1).

78651649 is an equidigital number, since it uses as much as digits as its factorization.

78651649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 46.

The square root of 78651649 is about 8868.5764923126. The cubic root of 78651649 is about 428.4524304909.

The spelling of 78651649 in words is "seventy-eight million, six hundred fifty-one thousand, six hundred forty-nine".