16664352121 has 2 divisors, whose sum is σ = 16664352122. Its totient is φ = 16664352120.

The previous prime is 16664352113. The next prime is 16664352151. The reversal of 16664352121 is 12125346661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15636252025 + 1028100096 = 125045^2 + 32064^2 .

It is an emirp because it is prime and its reverse (12125346661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16664352121 - 2³ = 16664352113 is a prime.

It is a super-2 number, since 2×16664352121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16664352151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8332176060 + 8332176061.

It is an arithmetic number, because the mean of its divisors is an integer number (8332176061).

Almost surely, 2^16664352121 is an apocalyptic number.

It is an amenable number.

16664352121 is a deficient number, since it is larger than the sum of its proper divisors (1).

16664352121 is an equidigital number, since it uses as much as digits as its factorization.

16664352121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 37.

Adding to 16664352121 its reverse (12125346661), we get a palindrome (28789698782).

The spelling of 16664352121 in words is "sixteen billion, six hundred sixty-four million, three hundred fifty-two thousand, one hundred twenty-one".