78919649 has 2 divisors, whose sum is σ = 78919650. Its totient is φ = 78919648.

The previous prime is 78919591. The next prime is 78919699. The reversal of 78919649 is 94691987.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53919649 + 25000000 = 7343^2 + 5000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78919649 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78919649.

It is not a weakly prime, because it can be changed into another prime (78919699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39459824 + 39459825.

It is an arithmetic number, because the mean of its divisors is an integer number (39459825).

Almost surely, 2^78919649 is an apocalyptic number.

It is an amenable number.

78919649 is a deficient number, since it is larger than the sum of its proper divisors (1).

78919649 is an equidigital number, since it uses as much as digits as its factorization.

78919649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 53.

The square root of 78919649 is about 8883.6731704853. The cubic root of 78919649 is about 428.9385193798.

The spelling of 78919649 in words is "seventy-eight million, nine hundred nineteen thousand, six hundred forty-nine".