16684521 has 32 divisors (see below), whose sum is σ = 26484480. Its totient is φ = 9144576.

The previous prime is 16684513. The next prime is 16684523. The reversal of 16684521 is 12548661.

It is not a de Polignac number, because 16684521 - 2³ = 16684513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16684523) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 84595 + ... + 84791.

It is an arithmetic number, because the mean of its divisors is an integer number (827640).

Almost surely, 2^16684521 is an apocalyptic number.

It is an amenable number.

16684521 is a deficient number, since it is larger than the sum of its proper divisors (9799959).

16684521 is a wasteful number, since it uses less digits than its factorization.

16684521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353.

The product of its digits is 11520, while the sum is 33.

The square root of 16684521 is about 4084.6690196392. The cubic root of 16684521 is about 255.5276578732.

It can be divided in two parts, 16684 and 521, that added together give a triangular number (17205 = T₁₈₅).

The spelling of 16684521 in words is "sixteen million, six hundred eighty-four thousand, five hundred twenty-one".