81321223 has 2 divisors, whose sum is σ = 81321224. Its totient is φ = 81321222.

The previous prime is 81321181. The next prime is 81321269. The reversal of 81321223 is 32212318.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81321223 is a prime.

It is a super-2 number, since 2×81321223² = 13226282620431458, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81321194 and 81321203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81321323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40660611 + 40660612.

It is an arithmetic number, because the mean of its divisors is an integer number (40660612).

Almost surely, 2^81321223 is an apocalyptic number.

81321223 is a deficient number, since it is larger than the sum of its proper divisors (1).

81321223 is an equidigital number, since it uses as much as digits as its factorization.

81321223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 22.

The square root of 81321223 is about 9017.8280644510. The cubic root of 81321223 is about 433.2460719097.

It can be divided in two parts, 8 and 1321223, that added together give a palindrome (1321231).

The spelling of 81321223 in words is "eighty-one million, three hundred twenty-one thousand, two hundred twenty-three".