81992293 has 2 divisors, whose sum is σ = 81992294. Its totient is φ = 81992292.

The previous prime is 81992269. The next prime is 81992311. The reversal of 81992293 is 39229918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71115489 + 10876804 = 8433^2 + 3298^2 .

It is a cyclic number.

It is not a de Polignac number, because 81992293 - 2²⁵ = 48437861 is a prime.

It is a super-3 number, since 3×81992293³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81992243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40996146 + 40996147.

It is an arithmetic number, because the mean of its divisors is an integer number (40996147).

Almost surely, 2^81992293 is an apocalyptic number.

It is an amenable number.

81992293 is a deficient number, since it is larger than the sum of its proper divisors (1).

81992293 is an equidigital number, since it uses as much as digits as its factorization.

81992293 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 43.

The square root of 81992293 is about 9054.9595802521. The cubic root of 81992293 is about 434.4345372078.

The spelling of 81992293 in words is "eighty-one million, nine hundred ninety-two thousand, two hundred ninety-three".