16197121 has 4 divisors (see below), whose sum is σ = 16255044. Its totient is φ = 16139200.

The previous prime is 16197119. The next prime is 16197149. The reversal of 16197121 is 12179161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4260096 + 11937025 = 2064^2 + 3455^2 .

It is a cyclic number.

It is not a de Polignac number, because 16197121 - 2¹ = 16197119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16197121.

It is not an unprimeable number, because it can be changed into a prime (16197151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28540 + ... + 29101.

It is an arithmetic number, because the mean of its divisors is an integer number (4063761).

Almost surely, 2^16197121 is an apocalyptic number.

It is an amenable number.

16197121 is a deficient number, since it is larger than the sum of its proper divisors (57923).

16197121 is an equidigital number, since it uses as much as digits as its factorization.

16197121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57922.

The product of its digits is 756, while the sum is 28.

The square root of 16197121 is about 4024.5646969579. The cubic root of 16197121 is about 253.0148095504.

The spelling of 16197121 in words is "sixteen million, one hundred ninety-seven thousand, one hundred twenty-one".