16501 has 4 divisors (see below), whose sum is σ = 17100. Its totient is φ = 15904.

The previous prime is 16493. The next prime is 16519. The reversal of 16501 is 10561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10561 = 59 ⋅179.

It can be written as a sum of positive squares in 2 ways, for example, as 5476 + 11025 = 74^2 + 105^2 .

It is a cyclic number.

It is not a de Polignac number, because 16501 - 2³ = 16493 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561) 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, 256 + ... + 313.

It is an arithmetic number, because the mean of its divisors is an integer number (4275).

2¹⁶⁵⁰¹ is an apocalyptic number.

It is an amenable number.

16501 is a deficient number, since it is larger than the sum of its proper divisors (599).

16501 is an equidigital number, since it uses as much as digits as its factorization.

16501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 598.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 16501 is about 128.4562182224. The cubic root of 16501 is about 25.4587311453.

Subtracting from 16501 its product of nonzero digits (30), we obtain a triangular number (16471 = T₁₈₁).

The spelling of 16501 in words is "sixteen thousand, five hundred one".