18933981 has 8 divisors (see below), whose sum is σ = 27540384. Its totient is φ = 11475120.

The previous prime is 18933977. The next prime is 18934001.

It is a happy number.

18933981 is nontrivially palindromic in base 10.

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

It is not a de Polignac number, because 18933981 - 2² = 18933977 is a prime.

It is a super-2 number, since 2×18933981² = 716991273016722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18931981) 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, 286846 + ... + 286911.

It is an arithmetic number, because the mean of its divisors is an integer number (3442548).

Almost surely, 2^18933981 is an apocalyptic number.

18933981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18933981 is a deficient number, since it is larger than the sum of its proper divisors (8606403).

18933981 is a wasteful number, since it uses less digits than its factorization.

18933981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573771.

The product of its digits is 46656, while the sum is 42.

The square root of 18933981 is about 4351.3194550619. The cubic root of 18933981 is about 266.5307444464.

It can be divided in two parts, 189339 and 81, that added together give a triangular number (189420 = T₆₁₅).

The spelling of 18933981 in words is "eighteen million, nine hundred thirty-three thousand, nine hundred eighty-one".