78306256891 has 2 divisors, whose sum is σ = 78306256892. Its totient is φ = 78306256890.

The previous prime is 78306256867. The next prime is 78306256907. The reversal of 78306256891 is 19865260387.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78306256891 - 2⁵ = 78306256859 is a prime.

It is a super-2 number, since 2×78306256891² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78306256811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39153128445 + 39153128446.

It is an arithmetic number, because the mean of its divisors is an integer number (39153128446).

Almost surely, 2^78306256891 is an apocalyptic number.

78306256891 is a deficient number, since it is larger than the sum of its proper divisors (1).

78306256891 is an equidigital number, since it uses as much as digits as its factorization.

78306256891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 78306256891 in words is "seventy-eight billion, three hundred six million, two hundred fifty-six thousand, eight hundred ninety-one".