18420281 has 8 divisors (see below), whose sum is σ = 20183904. Its totient is φ = 16671520.

The previous prime is 18420271. The next prime is 18420289. The reversal of 18420281 is 18202481.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18420281 - 2¹⁰ = 18419257 is a prime.

It is a super-2 number, since 2×18420281² = 678613504237922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18420281.

It is not an unprimeable number, because it can be changed into a prime (18420289) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1031 + ... + 6156.

It is an arithmetic number, because the mean of its divisors is an integer number (2522988).

Almost surely, 2^18420281 is an apocalyptic number.

18420281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18420281 is a deficient number, since it is larger than the sum of its proper divisors (1763623).

18420281 is a wasteful number, since it uses less digits than its factorization.

18420281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7431.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 18420281 is about 4291.8854830948. The cubic root of 18420281 is about 264.0981852803.

The spelling of 18420281 in words is "eighteen million, four hundred twenty thousand, two hundred eighty-one".