81786719579 has 2 divisors, whose sum is σ = 81786719580. Its totient is φ = 81786719578.

The previous prime is 81786719537. The next prime is 81786719611. The reversal of 81786719579 is 97591768718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81786719579 - 2⁸ = 81786719323 is a prime.

It is not a weakly prime, because it can be changed into another prime (81786713579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40893359789 + 40893359790.

It is an arithmetic number, because the mean of its divisors is an integer number (40893359790).

Almost surely, 2^81786719579 is an apocalyptic number.

81786719579 is a deficient number, since it is larger than the sum of its proper divisors (1).

81786719579 is an equidigital number, since it uses as much as digits as its factorization.

81786719579 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53343360, while the sum is 68.

The spelling of 81786719579 in words is "eighty-one billion, seven hundred eighty-six million, seven hundred nineteen thousand, five hundred seventy-nine".