16002121 has 4 divisors (see below), whose sum is σ = 16023700. Its totient is φ = 15980544.

The previous prime is 16002109. The next prime is 16002163. The reversal of 16002121 is 12120061.

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 5112121 + 10890000 = 2261^2 + 3300^2 .

It is a cyclic number.

It is not a de Polignac number, because 16002121 - 2¹⁷ = 15871049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16002101) 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, 9636 + ... + 11173.

It is an arithmetic number, because the mean of its divisors is an integer number (4005925).

Almost surely, 2^16002121 is an apocalyptic number.

It is an amenable number.

16002121 is a deficient number, since it is larger than the sum of its proper divisors (21579).

16002121 is an equidigital number, since it uses as much as digits as its factorization.

16002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21578.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 16002121 is about 4000.2651162142. The cubic root of 16002121 is about 251.9953440393.

Adding to 16002121 its reverse (12120061), we get a palindrome (28122182).

It can be divided in two parts, 1600 and 2121, that added together give a square (3721 = 61²).

The spelling of 16002121 in words is "sixteen million, two thousand, one hundred twenty-one".