81733365420 has 384 divisors, whose sum is σ = 272583843840. Its totient is φ = 17913692160.

The previous prime is 81733365403. The next prime is 81733365421. The reversal of 81733365420 is 2456333718.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (81733365421) 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 127 ways as a sum of consecutive naturals, for example, 423488844 + ... + 423489036.

It is an arithmetic number, because the mean of its divisors is an integer number (709853760).

Almost surely, 2^81733365420 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 81733365420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136291921920).

81733365420 is an abundant number, since it is smaller than the sum of its proper divisors (190850478420).

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

81733365420 is a wasteful number, since it uses less digits than its factorization.

81733365420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 565 (or 563 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 42.

The spelling of 81733365420 in words is "eighty-one billion, seven hundred thirty-three million, three hundred sixty-five thousand, four hundred twenty".