16536521 has 4 divisors (see below), whose sum is σ = 16983492. Its totient is φ = 16089552.

The previous prime is 16536511. The next prime is 16536577. The reversal of 16536521 is 12563561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6071296 + 10465225 = 2464^2 + 3235^2 .

It is a cyclic number.

It is not a de Polignac number, because 16536521 - 2¹⁴ = 16520137 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16536511) 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, 223430 + ... + 223503.

It is an arithmetic number, because the mean of its divisors is an integer number (4245873).

Almost surely, 2^16536521 is an apocalyptic number.

It is an amenable number.

16536521 is a deficient number, since it is larger than the sum of its proper divisors (446971).

16536521 is an equidigital number, since it uses as much as digits as its factorization.

16536521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446970.

The product of its digits is 5400, while the sum is 29.

The square root of 16536521 is about 4066.5121418729. The cubic root of 16536521 is about 254.7698602820.

The spelling of 16536521 in words is "sixteen million, five hundred thirty-six thousand, five hundred twenty-one".