81900733824 has 256 divisors, whose sum is σ = 297503808000. Its totient is φ = 21600110592.

The previous prime is 81900733823. The next prime is 81900733921. The reversal of 81900733824 is 42833700918.

It is a self number, because there is not a number n which added to its sum of digits gives 81900733824.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81900733823) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 184287 + ... + 444705.

It is an arithmetic number, because the mean of its divisors is an integer number (1162124250).

Almost surely, 2^81900733824 is an apocalyptic number.

81900733824 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81900733824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148751904000).

81900733824 is an abundant number, since it is smaller than the sum of its proper divisors (215603074176).

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

81900733824 is a wasteful number, since it uses less digits than its factorization.

81900733824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260462 (or 260444 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 81900733824 in words is "eighty-one billion, nine hundred million, seven hundred thirty-three thousand, eight hundred twenty-four".