161801317 has 2 divisors, whose sum is σ = 161801318. Its totient is φ = 161801316.

The previous prime is 161801309. The next prime is 161801329. The reversal of 161801317 is 713108161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157602916 + 4198401 = 12554^2 + 2049^2 .

It is a cyclic number.

It is not a de Polignac number, because 161801317 - 2³ = 161801309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161801347) 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, 80900658 + 80900659.

It is an arithmetic number, because the mean of its divisors is an integer number (80900659).

Almost surely, 2^161801317 is an apocalyptic number.

It is an amenable number.

161801317 is a deficient number, since it is larger than the sum of its proper divisors (1).

161801317 is an equidigital number, since it uses as much as digits as its factorization.

161801317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 161801317 is about 12720.1146614329. The cubic root of 161801317 is about 544.9132280561.

Adding to 161801317 its reverse (713108161), we get a palindrome (874909478).

The spelling of 161801317 in words is "one hundred sixty-one million, eight hundred one thousand, three hundred seventeen".