78993091 has 2 divisors, whose sum is σ = 78993092. Its totient is φ = 78993090.

The previous prime is 78993077. The next prime is 78993097. The reversal of 78993091 is 19039987.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78993091 - 2⁵ = 78993059 is a prime.

It is not a weakly prime, because it can be changed into another prime (78993097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39496545 + 39496546.

It is an arithmetic number, because the mean of its divisors is an integer number (39496546).

Almost surely, 2^78993091 is an apocalyptic number.

78993091 is a deficient number, since it is larger than the sum of its proper divisors (1).

78993091 is an equidigital number, since it uses as much as digits as its factorization.

78993091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 78993091 is about 8887.8057472022. The cubic root of 78993091 is about 429.0715337234.

The spelling of 78993091 in words is "seventy-eight million, nine hundred ninety-three thousand, ninety-one".