181661825 has 12 divisors (see below), whose sum is σ = 225662640. Its totient is φ = 145070160.

The previous prime is 181661801. The next prime is 181661839. The reversal of 181661825 is 528166181.

It is not a de Polignac number, because 181661825 - 2⁸ = 181661569 is a prime.

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, 8486 + ... + 20864.

It is an arithmetic number, because the mean of its divisors is an integer number (18805220).

Almost surely, 2^181661825 is an apocalyptic number.

It is an amenable number.

181661825 is a deficient number, since it is larger than the sum of its proper divisors (44000815).

181661825 is a wasteful number, since it uses less digits than its factorization.

181661825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12976 (or 12971 counting only the distinct ones).

The product of its digits is 23040, while the sum is 38.

The square root of 181661825 is about 13478.1981362495. The cubic root of 181661825 is about 566.3538941016.

It can be divided in two parts, 18166 and 1825, that added together give a palindrome (19991).

The spelling of 181661825 in words is "one hundred eighty-one million, six hundred sixty-one thousand, eight hundred twenty-five".