81223623936 has 576 divisors, whose sum is σ = 297350000640. Its totient is φ = 21296701440.

The previous prime is 81223623863. The next prime is 81223623967. The reversal of 81223623936 is 63932632218.

81223623936 is a `hidden beast` number, since 8 + 12 + 2 + 3 + 623 + 9 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 81223623891 and 81223623900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 165424651 + ... + 165425141.

It is an arithmetic number, because the mean of its divisors is an integer number (516232640).

Almost surely, 2^81223623936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81223623936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148675000320).

81223623936 is an abundant number, since it is smaller than the sum of its proper divisors (216126376704).

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

81223623936 is a wasteful number, since it uses less digits than its factorization.

81223623936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799 (or 779 counting only the distinct ones).

The product of its digits is 559872, while the sum is 45.

The spelling of 81223623936 in words is "eighty-one billion, two hundred twenty-three million, six hundred twenty-three thousand, nine hundred thirty-six".