18159481 has 4 divisors (see below), whose sum is σ = 18785700. Its totient is φ = 17533264.

The previous prime is 18159473. The next prime is 18159503. The reversal of 18159481 is 18495181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9985600 + 8173881 = 3160^2 + 2859^2 .

It is a cyclic number.

It is not a de Polignac number, because 18159481 - 2³ = 18159473 is a prime.

It is a super-2 number, since 2×18159481² = 659533500378722, 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 18159481.

It is not an unprimeable number, because it can be changed into a prime (18159431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 313066 + ... + 313123.

It is an arithmetic number, because the mean of its divisors is an integer number (4696425).

Almost surely, 2^18159481 is an apocalyptic number.

It is an amenable number.

18159481 is a deficient number, since it is larger than the sum of its proper divisors (626219).

18159481 is an equidigital number, since it uses as much as digits as its factorization.

18159481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626218.

The product of its digits is 11520, while the sum is 37.

The square root of 18159481 is about 4261.3942554051. The cubic root of 18159481 is about 262.8458618656.

The spelling of 18159481 in words is "eighteen million, one hundred fifty-nine thousand, four hundred eighty-one".