81537068933 has 2 divisors, whose sum is σ = 81537068934. Its totient is φ = 81537068932.

The previous prime is 81537068923. The next prime is 81537068953. The reversal of 81537068933 is 33986073518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54777998209 + 26759070724 = 234047^2 + 163582^2 .

It is a cyclic number.

It is not a de Polignac number, because 81537068933 - 2⁴ = 81537068917 is a prime.

It is a super-2 number, since 2×81537068933² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81537068923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40768534466 + 40768534467.

It is an arithmetic number, because the mean of its divisors is an integer number (40768534467).

Almost surely, 2^81537068933 is an apocalyptic number.

It is an amenable number.

81537068933 is a deficient number, since it is larger than the sum of its proper divisors (1).

81537068933 is an equidigital number, since it uses as much as digits as its factorization.

81537068933 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3265920, while the sum is 53.

The spelling of 81537068933 in words is "eighty-one billion, five hundred thirty-seven million, sixty-eight thousand, nine hundred thirty-three".