81355223 has 2 divisors, whose sum is σ = 81355224. Its totient is φ = 81355222.

The previous prime is 81355213. The next prime is 81355229. The reversal of 81355223 is 32255318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81355223 - 2¹⁸ = 81093079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81355229) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40677611 + 40677612.

It is an arithmetic number, because the mean of its divisors is an integer number (40677612).

Almost surely, 2^81355223 is an apocalyptic number.

81355223 is a deficient number, since it is larger than the sum of its proper divisors (1).

81355223 is an equidigital number, since it uses as much as digits as its factorization.

81355223 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7200, while the sum is 29.

The square root of 81355223 is about 9019.7130220423. The cubic root of 81355223 is about 433.3064428415.

The spelling of 81355223 in words is "eighty-one million, three hundred fifty-five thousand, two hundred twenty-three".