18028981 has 8 divisors (see below), whose sum is σ = 18720000. Its totient is φ = 17342640.

The previous prime is 18028973. The next prime is 18028999. The reversal of 18028981 is 18982081.

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 18028981 - 2³ = 18028973 is a prime.

It is a super-2 number, since 2×18028981² = 650088311796722, 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 18028981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18028921) 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, 8020 + ... + 10018.

It is an arithmetic number, because the mean of its divisors is an integer number (2340000).

Almost surely, 2^18028981 is an apocalyptic number.

It is an amenable number.

18028981 is a deficient number, since it is larger than the sum of its proper divisors (691019).

18028981 is a wasteful number, since it uses less digits than its factorization.

18028981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2339.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 18028981 is about 4246.0547570657. The cubic root of 18028981 is about 262.2147153109.

It can be divided in two parts, 180 and 28981, that added together give a triangular number (29161 = T₂₄₁).

The spelling of 18028981 in words is "eighteen million, twenty-eight thousand, nine hundred eighty-one".