18026981 has 4 divisors (see below), whose sum is σ = 20602272. Its totient is φ = 15451692.

The previous prime is 18026959. The next prime is 18027011. The reversal of 18026981 is 18962081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18962081 = 293 ⋅64717.

It is a cyclic number.

It is not a de Polignac number, because 18026981 - 2¹⁸ = 17764837 is a prime.

It is a super-2 number, since 2×18026981² = 649944087948722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18026941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1287635 + ... + 1287648.

It is an arithmetic number, because the mean of its divisors is an integer number (5150568).

Almost surely, 2^18026981 is an apocalyptic number.

It is an amenable number.

18026981 is a deficient number, since it is larger than the sum of its proper divisors (2575291).

18026981 is an equidigital number, since it uses as much as digits as its factorization.

18026981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2575290.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 18026981 is about 4245.8192377915. The cubic root of 18026981 is about 262.2050189074.

The spelling of 18026981 in words is "eighteen million, twenty-six thousand, nine hundred eighty-one".