78991093 has 2 divisors, whose sum is σ = 78991094. Its totient is φ = 78991092.

The previous prime is 78991013. The next prime is 78991097. The reversal of 78991093 is 39019987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78446449 + 544644 = 8857^2 + 738^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78991093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78991097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39495546 + 39495547.

It is an arithmetic number, because the mean of its divisors is an integer number (39495547).

Almost surely, 2^78991093 is an apocalyptic number.

It is an amenable number.

78991093 is a deficient number, since it is larger than the sum of its proper divisors (1).

78991093 is an equidigital number, since it uses as much as digits as its factorization.

78991093 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 78991093 is about 8887.6933452949. The cubic root of 78991093 is about 429.0679161405.

The spelling of 78991093 in words is "seventy-eight million, nine hundred ninety-one thousand, ninety-three".