81825128 has 32 divisors (see below), whose sum is σ = 191280960. Its totient is φ = 31879680.

The previous prime is 81825127. The next prime is 81825137. The reversal of 81825128 is 82152818.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65801 + ... + 67032.

It is an arithmetic number, because the mean of its divisors is an integer number (5977530).

Almost surely, 2^81825128 is an apocalyptic number.

81825128 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

81825128 is an abundant number, since it is smaller than the sum of its proper divisors (109455832).

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

81825128 is a wasteful number, since it uses less digits than its factorization.

81825128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132857 (or 132853 counting only the distinct ones).

The product of its digits is 10240, while the sum is 35.

The square root of 81825128 is about 9045.7242938308. The cubic root of 81825128 is about 434.1390961911.

The spelling of 81825128 in words is "eighty-one million, eight hundred twenty-five thousand, one hundred twenty-eight".