78790661 has 2 divisors, whose sum is σ = 78790662. Its totient is φ = 78790660.

The previous prime is 78790637. The next prime is 78790669. The reversal of 78790661 is 16609787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62710561 + 16080100 = 7919^2 + 4010^2 .

It is an emirp because it is prime and its reverse (16609787) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78790661 - 2¹⁸ = 78528517 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78790669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39395330 + 39395331.

It is an arithmetic number, because the mean of its divisors is an integer number (39395331).

Almost surely, 2^78790661 is an apocalyptic number.

It is an amenable number.

78790661 is a deficient number, since it is larger than the sum of its proper divisors (1).

78790661 is an equidigital number, since it uses as much as digits as its factorization.

78790661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 44.

The square root of 78790661 is about 8876.4103668093. The cubic root of 78790661 is about 428.7047031169.

The spelling of 78790661 in words is "seventy-eight million, seven hundred ninety thousand, six hundred sixty-one".