81985120 has 96 divisors (see below), whose sum is σ = 224695296. Its totient is φ = 27686400.

The previous prime is 81985103. The next prime is 81985121. The reversal of 81985120 is 2158918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81985121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79005 + ... + 80035.

It is an arithmetic number, because the mean of its divisors is an integer number (2340576).

Almost surely, 2^81985120 is an apocalyptic number.

81985120 is a gapful number since it is divisible by the number (80) 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 81985120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112347648).

81985120 is an abundant number, since it is smaller than the sum of its proper divisors (142710176).

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

81985120 is a wasteful number, since it uses less digits than its factorization.

81985120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124 (or 1116 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 81985120 is about 9054.5634903070. The cubic root of 81985120 is about 434.4218681723.

The spelling of 81985120 in words is "eighty-one million, nine hundred eighty-five thousand, one hundred twenty".