81825120 has 384 divisors, whose sum is σ = 325140480. Its totient is φ = 19077120.

The previous prime is 81825091. The next prime is 81825127. The reversal of 81825120 is 2152818.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81825127) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1740937 + ... + 1740983.

It is an arithmetic number, because the mean of its divisors is an integer number (846720).

Almost surely, 2^81825120 is an apocalyptic number.

81825120 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 81825120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162570240).

81825120 is an abundant number, since it is smaller than the sum of its proper divisors (243315360).

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

81825120 is a wasteful number, since it uses less digits than its factorization.

81825120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 81825120 is about 9045.7238516329. The cubic root of 81825120 is about 434.1390820426.

Adding to 81825120 its reverse (2152818), we get a palindrome (83977938).

The spelling of 81825120 in words is "eighty-one million, eight hundred twenty-five thousand, one hundred twenty".