81223011 has 6 divisors (see below), whose sum is σ = 117322140. Its totient is φ = 54148668.

The previous prime is 81222983. The next prime is 81223031. The reversal of 81223011 is 11032218.

It is not a de Polignac number, because 81223011 - 2⁵ = 81222979 is a prime.

It is a super-2 number, since 2×81223011² = 13194355031812242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81223031) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4512381 + ... + 4512398.

It is an arithmetic number, because the mean of its divisors is an integer number (19553690).

Almost surely, 2^81223011 is an apocalyptic number.

81223011 is a deficient number, since it is larger than the sum of its proper divisors (36099129).

81223011 is a wasteful number, since it uses less digits than its factorization.

81223011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9024785 (or 9024782 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 81223011 is about 9012.3809839576. The cubic root of 81223011 is about 433.0715905857.

Adding to 81223011 its reverse (11032218), we get a palindrome (92255229).

The spelling of 81223011 in words is "eighty-one million, two hundred twenty-three thousand, eleven".