16611121 has 4 divisors (see below), whose sum is σ = 16658532. Its totient is φ = 16563712.

The previous prime is 16611107. The next prime is 16611131. The reversal of 16611121 is 12111661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12111661 = 1483 ⋅8167.

It can be written as a sum of positive squares in 2 ways, for example, as 3186225 + 13424896 = 1785^2 + 3664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16611121 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16611131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23176 + ... + 23881.

It is an arithmetic number, because the mean of its divisors is an integer number (4164633).

Almost surely, 2^16611121 is an apocalyptic number.

It is an amenable number.

16611121 is a deficient number, since it is larger than the sum of its proper divisors (47411).

16611121 is an equidigital number, since it uses as much as digits as its factorization.

16611121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47410.

The product of its digits is 72, while the sum is 19.

The square root of 16611121 is about 4075.6743000392. The cubic root of 16611121 is about 255.1523938495.

Adding to 16611121 its reverse (12111661), we get a palindrome (28722782).

The spelling of 16611121 in words is "sixteen million, six hundred eleven thousand, one hundred twenty-one".