16311521 has 2 divisors, whose sum is σ = 16311522. Its totient is φ = 16311520.

The previous prime is 16311509. The next prime is 16311571. The reversal of 16311521 is 12511361.

16311521 is nontrivially palindromic in base 12.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9834496 + 6477025 = 3136^2 + 2545^2 .

It is an emirp because it is prime and its reverse (12511361) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16311521 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16311493 and 16311502.

It is not a weakly prime, because it can be changed into another prime (16311571) 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, 8155760 + 8155761.

It is an arithmetic number, because the mean of its divisors is an integer number (8155761).

Almost surely, 2^16311521 is an apocalyptic number.

It is an amenable number.

16311521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16311521 is an equidigital number, since it uses as much as digits as its factorization.

16311521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 20.

The square root of 16311521 is about 4038.7524063750. The cubic root of 16311521 is about 253.6090924188.

Adding to 16311521 its reverse (12511361), we get a palindrome (28822882).

The spelling of 16311521 in words is "sixteen million, three hundred eleven thousand, five hundred twenty-one".