18072281 has 2 divisors, whose sum is σ = 18072282. Its totient is φ = 18072280.

The previous prime is 18072259. The next prime is 18072289. The reversal of 18072281 is 18227081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9610000 + 8462281 = 3100^2 + 2909^2 .

It is an emirp because it is prime and its reverse (18227081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18072281 - 2¹⁰ = 18071257 is a prime.

It is a super-2 number, since 2×18072281² = 653214681085922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18072289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9036140 + 9036141.

It is an arithmetic number, because the mean of its divisors is an integer number (9036141).

Almost surely, 2^18072281 is an apocalyptic number.

It is an amenable number.

18072281 is a deficient number, since it is larger than the sum of its proper divisors (1).

18072281 is an equidigital number, since it uses as much as digits as its factorization.

18072281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 18072281 is about 4251.1505501452. The cubic root of 18072281 is about 262.4244668543.

The spelling of 18072281 in words is "eighteen million, seventy-two thousand, two hundred eighty-one".