78748661 has 2 divisors, whose sum is σ = 78748662. Its totient is φ = 78748660.

The previous prime is 78748639. The next prime is 78748667. The reversal of 78748661 is 16684787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67732900 + 11015761 = 8230^2 + 3319^2 .

It is a cyclic number.

It is not a de Polignac number, because 78748661 - 2²² = 74554357 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78748667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39374330 + 39374331.

It is an arithmetic number, because the mean of its divisors is an integer number (39374331).

Almost surely, 2^78748661 is an apocalyptic number.

It is an amenable number.

78748661 is a deficient number, since it is larger than the sum of its proper divisors (1).

78748661 is an equidigital number, since it uses as much as digits as its factorization.

78748661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 47.

The square root of 78748661 is about 8874.0442302256. The cubic root of 78748661 is about 428.6285147396.

The spelling of 78748661 in words is "seventy-eight million, seven hundred forty-eight thousand, six hundred sixty-one".