81121223232 has 210 divisors, whose sum is σ = 271261046758. Its totient is φ = 23177097216.

The previous prime is 81121223171. The next prime is 81121223251. The reversal of 81121223232 is 23232212118.

It can be written as a sum of positive squares in only one way, i.e., 80324629056 + 796594176 = 283416^2 + 28224^2 .

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 = 81121223196 and 81121223205.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 1353648 + ... + 1412304.

Almost surely, 2^81121223232 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 81121223232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135630523379).

81121223232 is an abundant number, since it is smaller than the sum of its proper divisors (190139823526).

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

81121223232 is an equidigital number, since it uses as much as digits as its factorization.

81121223232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58703 (or 58669 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The spelling of 81121223232 in words is "eighty-one billion, one hundred twenty-one million, two hundred twenty-three thousand, two hundred thirty-two".