78810267521 has 2 divisors, whose sum is σ = 78810267522. Its totient is φ = 78810267520.

The previous prime is 78810267491. The next prime is 78810267551. The reversal of 78810267521 is 12576201887.

It is a balanced prime because it is at equal distance from previous prime (78810267491) and next prime (78810267551).

It can be written as a sum of positive squares in only one way, i.e., 75108883600 + 3701383921 = 274060^2 + 60839^2 .

It is an emirp because it is prime and its reverse (12576201887) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78810267521 - 2¹⁴ = 78810251137 is a prime.

It is a super-2 number, since 2×78810267521² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78810267551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39405133760 + 39405133761.

It is an arithmetic number, because the mean of its divisors is an integer number (39405133761).

Almost surely, 2^78810267521 is an apocalyptic number.

It is an amenable number.

78810267521 is a deficient number, since it is larger than the sum of its proper divisors (1).

78810267521 is an equidigital number, since it uses as much as digits as its factorization.

78810267521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 376320, while the sum is 47.

The spelling of 78810267521 in words is "seventy-eight billion, eight hundred ten million, two hundred sixty-seven thousand, five hundred twenty-one".