81351577499 has 2 divisors, whose sum is σ = 81351577500. Its totient is φ = 81351577498.

The previous prime is 81351577457. The next prime is 81351577511. The reversal of 81351577499 is 99477515318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81351577499 - 2¹⁶ = 81351511963 is a prime.

It is not a weakly prime, because it can be changed into another prime (81351577429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40675788749 + 40675788750.

It is an arithmetic number, because the mean of its divisors is an integer number (40675788750).

Almost surely, 2^81351577499 is an apocalyptic number.

81351577499 is a deficient number, since it is larger than the sum of its proper divisors (1).

81351577499 is an equidigital number, since it uses as much as digits as its factorization.

81351577499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9525600, while the sum is 59.

The spelling of 81351577499 in words is "eighty-one billion, three hundred fifty-one million, five hundred seventy-seven thousand, four hundred ninety-nine".