18210981 has 8 divisors (see below), whose sum is σ = 25064704. Its totient is φ = 11748960.

The previous prime is 18210977. The next prime is 18210989. The reversal of 18210981 is 18901281.

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

It is not a de Polignac number, because 18210981 - 2² = 18210977 is a prime.

It is a super-2 number, since 2×18210981² = 663279657964722, 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 (18210989) 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 7 ways as a sum of consecutive naturals, for example, 97816 + ... + 98001.

It is an arithmetic number, because the mean of its divisors is an integer number (3133088).

Almost surely, 2^18210981 is an apocalyptic number.

It is an amenable number.

18210981 is a deficient number, since it is larger than the sum of its proper divisors (6853723).

18210981 is a wasteful number, since it uses less digits than its factorization.

18210981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195851.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 18210981 is about 4267.4326005222. The cubic root of 18210981 is about 263.0941029088.

It can be divided in two parts, 18210 and 981, that added together give a palindrome (19191).

The spelling of 18210981 in words is "eighteen million, two hundred ten thousand, nine hundred eighty-one".