181609889 has 2 divisors, whose sum is σ = 181609890. Its totient is φ = 181609888.

The previous prime is 181609877. The next prime is 181609937. The reversal of 181609889 is 988906181.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125059489 + 56550400 = 11183^2 + 7520^2 .

It is a cyclic number.

It is not a de Polignac number, because 181609889 - 2¹² = 181605793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (181609829) by changing a digit.

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 as a sum of consecutive naturals, namely, 90804944 + 90804945.

It is an arithmetic number, because the mean of its divisors is an integer number (90804945).

Almost surely, 2^181609889 is an apocalyptic number.

It is an amenable number.

181609889 is a deficient number, since it is larger than the sum of its proper divisors (1).

181609889 is an equidigital number, since it uses as much as digits as its factorization.

181609889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 50.

The square root of 181609889 is about 13476.2713314923. The cubic root of 181609889 is about 566.2999165907.

The spelling of 181609889 in words is "one hundred eighty-one million, six hundred nine thousand, eight hundred eighty-nine".