81223536 has 40 divisors (see below), whose sum is σ = 212196240. Its totient is φ = 26768896.

The previous prime is 81223531. The next prime is 81223553. The reversal of 81223536 is 63532218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81223531) 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, 5235 + ... + 13778.

It is an arithmetic number, because the mean of its divisors is an integer number (5304906).

Almost surely, 2^81223536 is an apocalyptic number.

It is an amenable number.

81223536 is an abundant number, since it is smaller than the sum of its proper divisors (130972704).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81223536 is a wasteful number, since it uses less digits than its factorization.

81223536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19113 (or 19107 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 81223536 is about 9012.4101105087. The cubic root of 81223536 is about 433.0725236632.

The spelling of 81223536 in words is "eighty-one million, two hundred twenty-three thousand, five hundred thirty-six".