81660223 has 2 divisors, whose sum is σ = 81660224. Its totient is φ = 81660222.

The previous prime is 81660193. The next prime is 81660263. The reversal of 81660223 is 32206618.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81660223 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81660191 and 81660200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81660263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40830111 + 40830112.

It is an arithmetic number, because the mean of its divisors is an integer number (40830112).

Almost surely, 2^81660223 is an apocalyptic number.

81660223 is a deficient number, since it is larger than the sum of its proper divisors (1).

81660223 is an equidigital number, since it uses as much as digits as its factorization.

81660223 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 81660223 is about 9036.6046167795. The cubic root of 81660223 is about 433.8472548906.

The spelling of 81660223 in words is "eighty-one million, six hundred sixty thousand, two hundred twenty-three".