78511 has 2 divisors, whose sum is σ = 78512. Its totient is φ = 78510.

The previous prime is 78509. The next prime is 78517. The reversal of 78511 is 11587.

It is a weak prime.

It is an emirp because it is prime and its reverse (11587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78511 - 2¹ = 78509 is a prime.

Together with 78509, it forms a pair of twin primes.

It is a Chen prime.

78511 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39255 + 39256.

It is an arithmetic number, because the mean of its divisors is an integer number (39256).

2⁷⁸⁵¹¹ is an apocalyptic number.

78511 is a deficient number, since it is larger than the sum of its proper divisors (1).

78511 is an equidigital number, since it uses as much as digits as its factorization.

78511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 280, while the sum is 22.

The square root of 78511 is about 280.1981441766. The cubic root of 78511 is about 42.8196884408.

The spelling of 78511 in words is "seventy-eight thousand, five hundred eleven".