78056521 has 2 divisors, whose sum is σ = 78056522. Its totient is φ = 78056520.

The previous prime is 78056513. The next prime is 78056527. The reversal of 78056521 is 12565087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77246521 + 810000 = 8789^2 + 900^2 .

It is a cyclic number.

It is not a de Polignac number, because 78056521 - 2³ = 78056513 is a prime.

It is not a weakly prime, because it can be changed into another prime (78056527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39028260 + 39028261.

It is an arithmetic number, because the mean of its divisors is an integer number (39028261).

Almost surely, 2^78056521 is an apocalyptic number.

It is an amenable number.

78056521 is a deficient number, since it is larger than the sum of its proper divisors (1).

78056521 is an equidigital number, since it uses as much as digits as its factorization.

78056521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 78056521 is about 8834.9601583708. The cubic root of 78056521 is about 427.3690462183.

The spelling of 78056521 in words is "seventy-eight million, fifty-six thousand, five hundred twenty-one".