16443121 has 2 divisors, whose sum is σ = 16443122. Its totient is φ = 16443120.

The previous prime is 16443109. The next prime is 16443127. The reversal of 16443121 is 12134461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16313521 + 129600 = 4039^2 + 360^2 .

It is an emirp because it is prime and its reverse (12134461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16443121 - 2⁹ = 16442609 is a prime.

It is a super-3 number, since 3×16443121³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 16443092 and 16443101.

It is not a weakly prime, because it can be changed into another prime (16443127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8221560 + 8221561.

It is an arithmetic number, because the mean of its divisors is an integer number (8221561).

Almost surely, 2^16443121 is an apocalyptic number.

It is an amenable number.

16443121 is a deficient number, since it is larger than the sum of its proper divisors (1).

16443121 is an equidigital number, since it uses as much as digits as its factorization.

16443121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 22.

The square root of 16443121 is about 4055.0118372207. The cubic root of 16443121 is about 254.2892987844.

Adding to 16443121 its reverse (12134461), we get a palindrome (28577582).

The spelling of 16443121 in words is "sixteen million, four hundred forty-three thousand, one hundred twenty-one".