81445825 has 12 divisors (see below), whose sum is σ = 102212208. Its totient is φ = 64370000.

The previous prime is 81445817. The next prime is 81445841. The reversal of 81445825 is 52854418.

It is not a de Polignac number, because 81445825 - 2³ = 81445817 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17551 + ... + 21700.

It is an arithmetic number, because the mean of its divisors is an integer number (8517684).

Almost surely, 2^81445825 is an apocalyptic number.

It is an amenable number.

81445825 is a deficient number, since it is larger than the sum of its proper divisors (20766383).

81445825 is a wasteful number, since it uses less digits than its factorization.

81445825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39344 (or 39339 counting only the distinct ones).

The product of its digits is 51200, while the sum is 37.

The square root of 81445825 is about 9024.7340681042. The cubic root of 81445825 is about 433.4672350824.

The spelling of 81445825 in words is "eighty-one million, four hundred forty-five thousand, eight hundred twenty-five".