78561311 has 4 divisors (see below), whose sum is σ = 79180032. Its totient is φ = 77942592.

The previous prime is 78561283. The next prime is 78561331. The reversal of 78561311 is 11316587.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78561311 - 2⁶ = 78561247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78561331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309170 + ... + 309423.

It is an arithmetic number, because the mean of its divisors is an integer number (19795008).

Almost surely, 2^78561311 is an apocalyptic number.

78561311 is a deficient number, since it is larger than the sum of its proper divisors (618721).

78561311 is a wasteful number, since it uses less digits than its factorization.

78561311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618720.

The product of its digits is 5040, while the sum is 32.

The square root of 78561311 is about 8863.4818779078. The cubic root of 78561311 is about 428.2883298248.

Adding to 78561311 its reverse (11316587), we get a palindrome (89877898).

The spelling of 78561311 in words is "seventy-eight million, five hundred sixty-one thousand, three hundred eleven".