16316521 has 4 divisors (see below), whose sum is σ = 17571652. Its totient is φ = 15061392.

The previous prime is 16316507. The next prime is 16316551. The reversal of 16316521 is 12561361.

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 1960000 + 14356521 = 1400^2 + 3789^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16316521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16316501) 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, 627546 + ... + 627571.

It is an arithmetic number, because the mean of its divisors is an integer number (4392913).

Almost surely, 2^16316521 is an apocalyptic number.

It is an amenable number.

16316521 is a deficient number, since it is larger than the sum of its proper divisors (1255131).

16316521 is a wasteful number, since it uses less digits than its factorization.

16316521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255130.

The product of its digits is 1080, while the sum is 25.

The square root of 16316521 is about 4039.3713619820. The cubic root of 16316521 is about 253.6350028560.

Adding to 16316521 its reverse (12561361), we get a palindrome (28877882).

The spelling of 16316521 in words is "sixteen million, three hundred sixteen thousand, five hundred twenty-one".