161312521 has 2 divisors, whose sum is σ = 161312522. Its totient is φ = 161312520.

The previous prime is 161312513. The next prime is 161312533. The reversal of 161312521 is 125213161.

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., 136422400 + 24890121 = 11680^2 + 4989^2 .

It is an emirp because it is prime and its reverse (125213161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161312521 - 2³ = 161312513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161312492 and 161312501.

It is not a weakly prime, because it can be changed into another prime (161312581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80656260 + 80656261.

It is an arithmetic number, because the mean of its divisors is an integer number (80656261).

Almost surely, 2^161312521 is an apocalyptic number.

It is an amenable number.

161312521 is a deficient number, since it is larger than the sum of its proper divisors (1).

161312521 is an equidigital number, since it uses as much as digits as its factorization.

161312521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 22.

The square root of 161312521 is about 12700.8866225945. The cubic root of 161312521 is about 544.3639534377.

Adding to 161312521 its reverse (125213161), we get a palindrome (286525682).

The spelling of 161312521 in words is "one hundred sixty-one million, three hundred twelve thousand, five hundred twenty-one".