16109021 has 4 divisors (see below), whose sum is σ = 16118844. Its totient is φ = 16099200.

The previous prime is 16109003. The next prime is 16109033. The reversal of 16109021 is 12090161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12090161 = 383 ⋅31567.

It can be written as a sum of positive squares in 2 ways, for example, as 4644025 + 11464996 = 2155^2 + 3386^2 .

It is a cyclic number.

It is not a de Polignac number, because 16109021 - 2²² = 11914717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16108984 and 16109002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16109521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1790 + ... + 5951.

It is an arithmetic number, because the mean of its divisors is an integer number (4029711).

Almost surely, 2^16109021 is an apocalyptic number.

It is an amenable number.

16109021 is a deficient number, since it is larger than the sum of its proper divisors (9823).

16109021 is an equidigital number, since it uses as much as digits as its factorization.

16109021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9822.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 16109021 is about 4013.6044897324. The cubic root of 16109021 is about 252.5552393604. Note that the first 3 decimals are identical.

Adding to 16109021 its reverse (12090161), we get a palindrome (28199182).

The spelling of 16109021 in words is "sixteen million, one hundred nine thousand, twenty-one".