18145281 has 48 divisors (see below), whose sum is σ = 31375232. Its totient is φ = 9123840.

The previous prime is 18145279. The next prime is 18145289. The reversal of 18145281 is 18254181.

It is a happy number.

It is not a de Polignac number, because 18145281 - 2¹ = 18145279 is a prime.

It is a super-2 number, since 2×18145281² = 658502445137922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18145289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 93921 + ... + 94113.

It is a Proth number, since it is equal to 2215 ⋅ 2¹³ + 1 and 2215 < 2¹³.

Almost surely, 2^18145281 is an apocalyptic number.

18145281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18145281 is a deficient number, since it is larger than the sum of its proper divisors (13229951).

18145281 is a wasteful number, since it uses less digits than its factorization.

18145281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262 (or 251 counting only the distinct ones).

The product of its digits is 2560, while the sum is 30.

The square root of 18145281 is about 4259.7278082056. The cubic root of 18145281 is about 262.7773322910. Note that the first 3 decimals are identical.

Subtracting 18145281 from its reverse (18254181), we obtain a square (108900 = 330²).

The spelling of 18145281 in words is "eighteen million, one hundred forty-five thousand, two hundred eighty-one".