78815941 has 2 divisors, whose sum is σ = 78815942. Its totient is φ = 78815940.

The previous prime is 78815923. The next prime is 78815951. The reversal of 78815941 is 14951887.

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., 72420100 + 6395841 = 8510^2 + 2529^2 .

It is an emirp because it is prime and its reverse (14951887) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78815941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78815951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39407970 + 39407971.

It is an arithmetic number, because the mean of its divisors is an integer number (39407971).

Almost surely, 2^78815941 is an apocalyptic number.

It is an amenable number.

78815941 is a deficient number, since it is larger than the sum of its proper divisors (1).

78815941 is an equidigital number, since it uses as much as digits as its factorization.

78815941 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80640, while the sum is 43.

The square root of 78815941 is about 8877.8342516630. The cubic root of 78815941 is about 428.7505482119.

The spelling of 78815941 in words is "seventy-eight million, eight hundred fifteen thousand, nine hundred forty-one".