78343591 has 2 divisors, whose sum is σ = 78343592. Its totient is φ = 78343590.

The previous prime is 78343567. The next prime is 78343609. The reversal of 78343591 is 19534387.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78343591 - 2¹⁹ = 77819303 is a prime.

It is a super-2 number, since 2×78343591² = 12275436501550562, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78343511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39171795 + 39171796.

It is an arithmetic number, because the mean of its divisors is an integer number (39171796).

Almost surely, 2^78343591 is an apocalyptic number.

78343591 is a deficient number, since it is larger than the sum of its proper divisors (1).

78343591 is an equidigital number, since it uses as much as digits as its factorization.

78343591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 40.

The square root of 78343591 is about 8851.1915017132. The cubic root of 78343591 is about 427.8923197682.

The spelling of 78343591 in words is "seventy-eight million, three hundred forty-three thousand, five hundred ninety-one".