81133223989 has 2 divisors, whose sum is σ = 81133223990. Its totient is φ = 81133223988.

The previous prime is 81133223987. The next prime is 81133224019. The reversal of 81133223989 is 98932233118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79839023364 + 1294200625 = 282558^2 + 35975^2 .

It is a cyclic number.

It is not a de Polignac number, because 81133223989 - 2¹ = 81133223987 is a prime.

Together with 81133223987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81133223981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40566611994 + 40566611995.

It is an arithmetic number, because the mean of its divisors is an integer number (40566611995).

Almost surely, 2^81133223989 is an apocalyptic number.

It is an amenable number.

81133223989 is a deficient number, since it is larger than the sum of its proper divisors (1).

81133223989 is an equidigital number, since it uses as much as digits as its factorization.

81133223989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The spelling of 81133223989 in words is "eighty-one billion, one hundred thirty-three million, two hundred twenty-three thousand, nine hundred eighty-nine".