81223031 has 2 divisors, whose sum is σ = 81223032. Its totient is φ = 81223030.

The previous prime is 81222983. The next prime is 81223049. The reversal of 81223031 is 13032218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81223031 - 2¹⁰ = 81222007 is a prime.

It is a super-2 number, since 2×81223031² = 13194361529653922, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81222994 and 81223012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81223531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40611515 + 40611516.

It is an arithmetic number, because the mean of its divisors is an integer number (40611516).

Almost surely, 2^81223031 is an apocalyptic number.

81223031 is a deficient number, since it is larger than the sum of its proper divisors (1).

81223031 is an equidigital number, since it uses as much as digits as its factorization.

81223031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 81223031 is about 9012.3820935422. The cubic root of 81223031 is about 433.0716261316.

Adding to 81223031 its reverse (13032218), we get a palindrome (94255249).

The spelling of 81223031 in words is "eighty-one million, two hundred twenty-three thousand, thirty-one".