18384981 has 8 divisors (see below), whose sum is σ = 25579200. Its totient is φ = 11723712.

The previous prime is 18384979. The next prime is 18384983. The reversal of 18384981 is 18948381.

It is an interprime number because it is at equal distance from previous prime (18384979) and next prime (18384983).

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

It is not a de Polignac number, because 18384981 - 2¹ = 18384979 is a prime.

It is a super-2 number, since 2×18384981² = 676015052740722, which contains 22 as substring.

It is a zygodrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18384983) 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, 133156 + ... + 133293.

It is an arithmetic number, because the mean of its divisors is an integer number (3197400).

Almost surely, 2^18384981 is an apocalyptic number.

It is an amenable number.

18384981 is a deficient number, since it is larger than the sum of its proper divisors (7194219).

18384981 is a wasteful number, since it uses less digits than its factorization.

18384981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266475.

The product of its digits is 55296, while the sum is 42.

The square root of 18384981 is about 4287.7710993009. The cubic root of 18384981 is about 263.9293744734.

The spelling of 18384981 in words is "eighteen million, three hundred eighty-four thousand, nine hundred eighty-one".