81928591499 has 2 divisors, whose sum is σ = 81928591500. Its totient is φ = 81928591498.

The previous prime is 81928591471. The next prime is 81928591513. The reversal of 81928591499 is 99419582918.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81928591499 is a prime.

It is not a weakly prime, because it can be changed into another prime (81928591469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40964295749 + 40964295750.

It is an arithmetic number, because the mean of its divisors is an integer number (40964295750).

Almost surely, 2^81928591499 is an apocalyptic number.

81928591499 is a deficient number, since it is larger than the sum of its proper divisors (1).

81928591499 is an equidigital number, since it uses as much as digits as its factorization.

81928591499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16796160, while the sum is 65.

The spelling of 81928591499 in words is "eighty-one billion, nine hundred twenty-eight million, five hundred ninety-one thousand, four hundred ninety-nine".