16012721 has 2 divisors, whose sum is σ = 16012722. Its totient is φ = 16012720.

The previous prime is 16012699. The next prime is 16012723. The reversal of 16012721 is 12721061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15880225 + 132496 = 3985^2 + 364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16012721 is a prime.

Together with 16012723, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 16012693 and 16012702.

It is not a weakly prime, because it can be changed into another prime (16012723) 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, 8006360 + 8006361.

It is an arithmetic number, because the mean of its divisors is an integer number (8006361).

Almost surely, 2^16012721 is an apocalyptic number.

It is an amenable number.

16012721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16012721 is an equidigital number, since it uses as much as digits as its factorization.

16012721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 16012721 is about 4001.5898090634. The cubic root of 16012721 is about 252.0509733537.

Adding to 16012721 its reverse (12721061), we get a palindrome (28733782).

The spelling of 16012721 in words is "sixteen million, twelve thousand, seven hundred twenty-one".