16861121 has 4 divisors (see below), whose sum is σ = 16911492. Its totient is φ = 16810752.

The previous prime is 16861111. The next prime is 16861129. The reversal of 16861121 is 12116861.

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 2146225 + 14714896 = 1465^2 + 3836^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16861121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16861129) 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, 24680 + ... + 25353.

It is an arithmetic number, because the mean of its divisors is an integer number (4227873).

Almost surely, 2^16861121 is an apocalyptic number.

It is an amenable number.

16861121 is a deficient number, since it is larger than the sum of its proper divisors (50371).

16861121 is an equidigital number, since it uses as much as digits as its factorization.

16861121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50370.

The product of its digits is 576, while the sum is 26.

The square root of 16861121 is about 4106.2295357177. The cubic root of 16861121 is about 256.4260534369.

Adding to 16861121 its reverse (12116861), we get a palindrome (28977982).

The spelling of 16861121 in words is "sixteen million, eight hundred sixty-one thousand, one hundred twenty-one".