181647121 has 2 divisors, whose sum is σ = 181647122. Its totient is φ = 181647120.

The previous prime is 181647119. The next prime is 181647127. The reversal of 181647121 is 121746181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180606721 + 1040400 = 13439^2 + 1020^2 .

It is a cyclic number.

It is not a de Polignac number, because 181647121 - 2¹ = 181647119 is a prime.

Together with 181647119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (181647127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90823560 + 90823561.

It is an arithmetic number, because the mean of its divisors is an integer number (90823561).

Almost surely, 2^181647121 is an apocalyptic number.

It is an amenable number.

181647121 is a deficient number, since it is larger than the sum of its proper divisors (1).

181647121 is an equidigital number, since it uses as much as digits as its factorization.

181647121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 31.

The square root of 181647121 is about 13477.6526517046. The cubic root of 181647121 is about 566.3386131579.

The spelling of 181647121 in words is "one hundred eighty-one million, six hundred forty-seven thousand, one hundred twenty-one".