81866463233 has 2 divisors, whose sum is σ = 81866463234. Its totient is φ = 81866463232.

The previous prime is 81866463223. The next prime is 81866463271. The reversal of 81866463233 is 33236466818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54339339664 + 27527123569 = 233108^2 + 165913^2 .

It is a cyclic number.

It is not a de Polignac number, because 81866463233 - 2¹² = 81866459137 is a prime.

It is not a weakly prime, because it can be changed into another prime (81866463223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40933231616 + 40933231617.

It is an arithmetic number, because the mean of its divisors is an integer number (40933231617).

Almost surely, 2^81866463233 is an apocalyptic number.

It is an amenable number.

81866463233 is a deficient number, since it is larger than the sum of its proper divisors (1).

81866463233 is an equidigital number, since it uses as much as digits as its factorization.

81866463233 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2985984, while the sum is 50.

The spelling of 81866463233 in words is "eighty-one billion, eight hundred sixty-six million, four hundred sixty-three thousand, two hundred thirty-three".