78675991 has 2 divisors, whose sum is σ = 78675992. Its totient is φ = 78675990.

The previous prime is 78675953. The next prime is 78676001. The reversal of 78675991 is 19957687.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78675991 - 2¹⁷ = 78544919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78675491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39337995 + 39337996.

It is an arithmetic number, because the mean of its divisors is an integer number (39337996).

Almost surely, 2^78675991 is an apocalyptic number.

78675991 is a deficient number, since it is larger than the sum of its proper divisors (1).

78675991 is an equidigital number, since it uses as much as digits as its factorization.

78675991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 952560, while the sum is 52.

The square root of 78675991 is about 8869.9487597167. The cubic root of 78675991 is about 428.4966266963.

The spelling of 78675991 in words is "seventy-eight million, six hundred seventy-five thousand, nine hundred ninety-one".