16563121 has 4 divisors (see below), whose sum is σ = 16724032. Its totient is φ = 16402212.

The previous prime is 16563109. The next prime is 16563133. The reversal of 16563121 is 12136561.

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.

It is an interprime number because it is at equal distance from previous prime (16563109) and next prime (16563133).

It is a cyclic number.

It is not a de Polignac number, because 16563121 - 2¹⁹ = 16038833 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16563181) 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, 80301 + ... + 80506.

It is an arithmetic number, because the mean of its divisors is an integer number (4181008).

Almost surely, 2^16563121 is an apocalyptic number.

It is an amenable number.

16563121 is a deficient number, since it is larger than the sum of its proper divisors (160911).

16563121 is a wasteful number, since it uses less digits than its factorization.

16563121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160910.

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

The square root of 16563121 is about 4069.7814437633. The cubic root of 16563121 is about 254.9063913749.

Adding to 16563121 its reverse (12136561), we get a palindrome (28699682).

The spelling of 16563121 in words is "sixteen million, five hundred sixty-three thousand, one hundred twenty-one".