16450642721 has 2 divisors, whose sum is σ = 16450642722. Its totient is φ = 16450642720.

The previous prime is 16450642709. The next prime is 16450642777. The reversal of 16450642721 is 12724605461.

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., 10586146321 + 5864496400 = 102889^2 + 76580^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16450642721 is a prime.

It is a super-3 number, since 3×16450642721³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (16450692721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8225321360 + 8225321361.

It is an arithmetic number, because the mean of its divisors is an integer number (8225321361).

Almost surely, 2^16450642721 is an apocalyptic number.

It is an amenable number.

16450642721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16450642721 is an equidigital number, since it uses as much as digits as its factorization.

16450642721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 16450642721 in words is "sixteen billion, four hundred fifty million, six hundred forty-two thousand, seven hundred twenty-one".