181803121 has 2 divisors, whose sum is σ = 181803122. Its totient is φ = 181803120.

The previous prime is 181803113. The next prime is 181803157. The reversal of 181803121 is 121308181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 107412496 + 74390625 = 10364^2 + 8625^2 .

It is an emirp because it is prime and its reverse (121308181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181803121 - 2³ = 181803113 is a prime.

It is equal to p_10124926 and since 181803121 and 10124926 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (181803161) 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, 90901560 + 90901561.

It is an arithmetic number, because the mean of its divisors is an integer number (90901561).

Almost surely, 2^181803121 is an apocalyptic number.

It is an amenable number.

181803121 is a deficient number, since it is larger than the sum of its proper divisors (1).

181803121 is an equidigital number, since it uses as much as digits as its factorization.

181803121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 181803121 is about 13483.4387676141. The cubic root of 181803121 is about 566.5006921450.

The spelling of 181803121 in words is "one hundred eighty-one million, eight hundred three thousand, one hundred twenty-one".