78965591 has 2 divisors, whose sum is σ = 78965592. Its totient is φ = 78965590.

The previous prime is 78965543. The next prime is 78965599. The reversal of 78965591 is 19556987.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78965591 - 2²⁶ = 11856727 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78965599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39482795 + 39482796.

It is an arithmetic number, because the mean of its divisors is an integer number (39482796).

Almost surely, 2^78965591 is an apocalyptic number.

78965591 is a deficient number, since it is larger than the sum of its proper divisors (1).

78965591 is an equidigital number, since it uses as much as digits as its factorization.

78965591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 50.

The square root of 78965591 is about 8886.2585490183. The cubic root of 78965591 is about 429.0217368085.

The spelling of 78965591 in words is "seventy-eight million, nine hundred sixty-five thousand, five hundred ninety-one".