16820281 has 2 divisors, whose sum is σ = 16820282. Its totient is φ = 16820280.

The previous prime is 16820273. The next prime is 16820299. The reversal of 16820281 is 18202861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13875625 + 2944656 = 3725^2 + 1716^2 .

It is an emirp because it is prime and its reverse (18202861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16820281 - 2³ = 16820273 is a prime.

It is a super-2 number, since 2×16820281² = 565843705837922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16820081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8410140 + 8410141.

It is an arithmetic number, because the mean of its divisors is an integer number (8410141).

Almost surely, 2^16820281 is an apocalyptic number.

It is an amenable number.

16820281 is a deficient number, since it is larger than the sum of its proper divisors (1).

16820281 is an equidigital number, since it uses as much as digits as its factorization.

16820281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 16820281 is about 4101.2535888433. The cubic root of 16820281 is about 256.2188527678.

It can be divided in two parts, 168 and 20281, that added together give a square (20449 = 143²).

The spelling of 16820281 in words is "sixteen million, eight hundred twenty thousand, two hundred eighty-one".