81223121 has 8 divisors (see below), whose sum is σ = 93495360. Its totient is φ = 69118128.

The previous prime is 81223073. The next prime is 81223133. The reversal of 81223121 is 12132218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81223121 - 2⁶ = 81223057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81223093 and 81223102.

It is not an unprimeable number, because it can be changed into a prime (81223141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40766 + ... + 42711.

It is an arithmetic number, because the mean of its divisors is an integer number (11686920).

Almost surely, 2^81223121 is an apocalyptic number.

It is an amenable number.

81223121 is a deficient number, since it is larger than the sum of its proper divisors (12272239).

81223121 is a wasteful number, since it uses less digits than its factorization.

81223121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83623.

The product of its digits is 192, while the sum is 20.

The square root of 81223121 is about 9012.3870866713. The cubic root of 81223121 is about 433.0717860880.

Adding to 81223121 its reverse (12132218), we get a palindrome (93355339).

The spelling of 81223121 in words is "eighty-one million, two hundred twenty-three thousand, one hundred twenty-one".