16624021 has 2 divisors, whose sum is σ = 16624022. Its totient is φ = 16624020.

The previous prime is 16624007. The next prime is 16624037. The reversal of 16624021 is 12042661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15920100 + 703921 = 3990^2 + 839^2 .

It is an emirp because it is prime and its reverse (12042661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16624021 - 2¹³ = 16615829 is a prime.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 16623983 and 16624001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16624001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8312010 + 8312011.

It is an arithmetic number, because the mean of its divisors is an integer number (8312011).

Almost surely, 2^16624021 is an apocalyptic number.

It is an amenable number.

16624021 is a deficient number, since it is larger than the sum of its proper divisors (1).

16624021 is an equidigital number, since it uses as much as digits as its factorization.

16624021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 16624021 is about 4077.2565531249. The cubic root of 16624021 is about 255.2184262024.

Adding to 16624021 its reverse (12042661), we get a palindrome (28666682).

The spelling of 16624021 in words is "sixteen million, six hundred twenty-four thousand, twenty-one".