16682721 has 8 divisors (see below), whose sum is σ = 24265824. Its totient is φ = 10110720.

The previous prime is 16682711. The next prime is 16682737. The reversal of 16682721 is 12728661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16682721 - 2¹³ = 16674529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 505537 = 16682721 / (1 + 6 + 6 + 8 + 2 + 7 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (16682711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252736 + ... + 252801.

It is an arithmetic number, because the mean of its divisors is an integer number (3033228).

Almost surely, 2^16682721 is an apocalyptic number.

16682721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16682721 is a deficient number, since it is larger than the sum of its proper divisors (7583103).

16682721 is a wasteful number, since it uses less digits than its factorization.

16682721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 505551.

The product of its digits is 8064, while the sum is 33.

The square root of 16682721 is about 4084.4486776063. The cubic root of 16682721 is about 255.5184683911.

The spelling of 16682721 in words is "sixteen million, six hundred eighty-two thousand, seven hundred twenty-one".