81223612 has 24 divisors (see below), whose sum is σ = 144023040. Its totient is φ = 40078080.

The previous prime is 81223591. The next prime is 81223619. The reversal of 81223612 is 21632218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81223619) 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, 142464 + ... + 143032.

It is an arithmetic number, because the mean of its divisors is an integer number (6000960).

Almost surely, 2^81223612 is an apocalyptic number.

It is an amenable number.

81223612 is a deficient number, since it is larger than the sum of its proper divisors (62799428).

81223612 is a wasteful number, since it uses less digits than its factorization.

81223612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981 (or 979 counting only the distinct ones).

The product of its digits is 1152, while the sum is 25.

The square root of 81223612 is about 9012.4143269160. The cubic root of 81223612 is about 433.0726587370.

The spelling of 81223612 in words is "eighty-one million, two hundred twenty-three thousand, six hundred twelve".