181375409 has 2 divisors, whose sum is σ = 181375410. Its totient is φ = 181375408.

The previous prime is 181375399. The next prime is 181375421. The reversal of 181375409 is 904573181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156175009 + 25200400 = 12497^2 + 5020^2 .

It is a cyclic number.

It is not a de Polignac number, because 181375409 - 2²⁴ = 164598193 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (181375429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90687704 + 90687705.

It is an arithmetic number, because the mean of its divisors is an integer number (90687705).

Almost surely, 2^181375409 is an apocalyptic number.

It is an amenable number.

181375409 is a deficient number, since it is larger than the sum of its proper divisors (1).

181375409 is an equidigital number, since it uses as much as digits as its factorization.

181375409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 181375409 is about 13467.5687857906. The cubic root of 181375409 is about 566.0560914082.

The spelling of 181375409 in words is "one hundred eighty-one million, three hundred seventy-five thousand, four hundred nine".