16623281 has 2 divisors, whose sum is σ = 16623282. Its totient is φ = 16623280.

The previous prime is 16623247. The next prime is 16623311. The reversal of 16623281 is 18232661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15335056 + 1288225 = 3916^2 + 1135^2 .

It is an emirp because it is prime and its reverse (18232661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16623281 - 2¹⁰ = 16622257 is a prime.

It is a super-2 number, since 2×16623281² = 552666942409922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16625281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8311640 + 8311641.

It is an arithmetic number, because the mean of its divisors is an integer number (8311641).

Almost surely, 2^16623281 is an apocalyptic number.

It is an amenable number.

16623281 is a deficient number, since it is larger than the sum of its proper divisors (1).

16623281 is an equidigital number, since it uses as much as digits as its factorization.

16623281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 29.

The square root of 16623281 is about 4077.1658048208. The cubic root of 16623281 is about 255.2146392237.

The spelling of 16623281 in words is "sixteen million, six hundred twenty-three thousand, two hundred eighty-one".