81217708224 has 56 divisors (see below), whose sum is σ = 217608668160. Its totient is φ = 26729873664.

The previous prime is 81217708223. The next prime is 81217708249. The reversal of 81217708224 is 42280771218.

It is a super-2 number, since 2×81217708224² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81217708223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2662104 + ... + 2692439.

Almost surely, 2^81217708224 is an apocalyptic number.

It is an amenable number.

81217708224 is an abundant number, since it is smaller than the sum of its proper divisors (136390959936).

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

81217708224 is a wasteful number, since it uses less digits than its factorization.

81217708224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5354637 (or 5354627 counting only the distinct ones).

The product of its (nonzero) digits is 100352, while the sum is 42.

The spelling of 81217708224 in words is "eighty-one billion, two hundred seventeen million, seven hundred eight thousand, two hundred twenty-four".