78778462649 has 2 divisors, whose sum is σ = 78778462650. Its totient is φ = 78778462648.

The previous prime is 78778462573. The next prime is 78778462699. The reversal of 78778462649 is 94626487787.

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., 77858857024 + 919605625 = 279032^2 + 30325^2 .

It is a cyclic number.

It is not a de Polignac number, because 78778462649 - 2¹² = 78778458553 is a prime.

It is not a weakly prime, because it can be changed into another prime (78778462699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39389231324 + 39389231325.

It is an arithmetic number, because the mean of its divisors is an integer number (39389231325).

Almost surely, 2^78778462649 is an apocalyptic number.

It is an amenable number.

78778462649 is a deficient number, since it is larger than the sum of its proper divisors (1).

78778462649 is an equidigital number, since it uses as much as digits as its factorization.

78778462649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 227598336, while the sum is 68.

The spelling of 78778462649 in words is "seventy-eight billion, seven hundred seventy-eight million, four hundred sixty-two thousand, six hundred forty-nine".