16987121 has 4 divisors (see below), whose sum is σ = 17881200. Its totient is φ = 16093044.

The previous prime is 16987111. The next prime is 16987123. The reversal of 16987121 is 12178961.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12178961 = 157 ⋅77573.

It is a cyclic number.

It is not a de Polignac number, because 16987121 - 2¹⁰ = 16986097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16987123) 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, 447011 + ... + 447048.

It is an arithmetic number, because the mean of its divisors is an integer number (4470300).

Almost surely, 2^16987121 is an apocalyptic number.

It is an amenable number.

16987121 is a deficient number, since it is larger than the sum of its proper divisors (894079).

16987121 is an equidigital number, since it uses as much as digits as its factorization.

16987121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894078.

The product of its digits is 6048, while the sum is 35.

The square root of 16987121 is about 4121.5435215463. The cubic root of 16987121 is about 257.0632102388.

The spelling of 16987121 in words is "sixteen million, nine hundred eighty-seven thousand, one hundred twenty-one".