81120211620 has 192 divisors, whose sum is σ = 268383338496. Its totient is φ = 17915189760.

The previous prime is 81120211553. The next prime is 81120211631. The reversal of 81120211620 is 2611202118.

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, 8809939 + ... + 8819141.

It is an arithmetic number, because the mean of its divisors is an integer number (1397829888).

Almost surely, 2^81120211620 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 81120211620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134191669248).

81120211620 is an abundant number, since it is smaller than the sum of its proper divisors (187263126876).

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

81120211620 is a wasteful number, since it uses less digits than its factorization.

81120211620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9930 (or 9928 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 24.

Adding to 81120211620 its reverse (2611202118), we get a palindrome (83731413738).

The spelling of 81120211620 in words is "eighty-one billion, one hundred twenty million, two hundred eleven thousand, six hundred twenty".