16451521 has 4 divisors (see below), whose sum is σ = 16479232. Its totient is φ = 16423812.

The previous prime is 16451489. The next prime is 16451573. The reversal of 16451521 is 12515461.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12515461 = 7 ⋅1787923.

It is a cyclic number.

It is not a de Polignac number, because 16451521 - 2⁵ = 16451489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16451581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12945 + ... + 14158.

It is an arithmetic number, because the mean of its divisors is an integer number (4119808).

Almost surely, 2^16451521 is an apocalyptic number.

It is an amenable number.

16451521 is a deficient number, since it is larger than the sum of its proper divisors (27711).

16451521 is an equidigital number, since it uses as much as digits as its factorization.

16451521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27710.

The product of its digits is 1200, while the sum is 25.

The square root of 16451521 is about 4056.0474602746. The cubic root of 16451521 is about 254.3325928055.

Adding to 16451521 its reverse (12515461), we get a palindrome (28966982).

The spelling of 16451521 in words is "sixteen million, four hundred fifty-one thousand, five hundred twenty-one".