18020381 has 2 divisors, whose sum is σ = 18020382. Its totient is φ = 18020380.

The previous prime is 18020351. The next prime is 18020389. The reversal of 18020381 is 18302081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15476356 + 2544025 = 3934^2 + 1595^2 .

It is a cyclic number.

It is not a de Polignac number, because 18020381 - 2¹⁰ = 18019357 is a prime.

It is a super-2 number, since 2×18020381² = 649468262770322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18020389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9010190 + 9010191.

It is an arithmetic number, because the mean of its divisors is an integer number (9010191).

Almost surely, 2^18020381 is an apocalyptic number.

It is an amenable number.

18020381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18020381 is an equidigital number, since it uses as much as digits as its factorization.

18020381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 18020381 is about 4245.0419314772. The cubic root of 18020381 is about 262.1730156865.

The spelling of 18020381 in words is "eighteen million, twenty thousand, three hundred eighty-one".