81923533129 has 2 divisors, whose sum is σ = 81923533130. Its totient is φ = 81923533128.

The previous prime is 81923533099. The next prime is 81923533207. The reversal of 81923533129 is 92133532918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74596173129 + 7327360000 = 273123^2 + 85600^2 .

It is a cyclic number.

It is not a de Polignac number, because 81923533129 - 2⁹ = 81923532617 is a prime.

It is a super-2 number, since 2×81923533129² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81923534129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40961766564 + 40961766565.

It is an arithmetic number, because the mean of its divisors is an integer number (40961766565).

Almost surely, 2^81923533129 is an apocalyptic number.

It is an amenable number.

81923533129 is a deficient number, since it is larger than the sum of its proper divisors (1).

81923533129 is an equidigital number, since it uses as much as digits as its factorization.

81923533129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 46.

The spelling of 81923533129 in words is "eighty-one billion, nine hundred twenty-three million, five hundred thirty-three thousand, one hundred twenty-nine".