16676721 has 6 divisors (see below), whose sum is σ = 24088610. Its totient is φ = 11117808.

The previous prime is 16676719. The next prime is 16676741. The reversal of 16676721 is 12767661.

It can be written as a sum of positive squares in only one way, i.e., 15800625 + 876096 = 3975^2 + 936^2 .

It is not a de Polignac number, because 16676721 - 2¹ = 16676719 is a prime.

It is a super-2 number, since 2×16676721² = 556226046623682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16676701) 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 5 ways as a sum of consecutive naturals, for example, 926476 + ... + 926493.

Almost surely, 2^16676721 is an apocalyptic number.

It is an amenable number.

16676721 is a deficient number, since it is larger than the sum of its proper divisors (7411889).

16676721 is a wasteful number, since it uses less digits than its factorization.

16676721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1852975 (or 1852972 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 16676721 is about 4083.7141182997. The cubic root of 16676721 is about 255.4878320090.

The spelling of 16676721 in words is "sixteen million, six hundred seventy-six thousand, seven hundred twenty-one".