18545381 has 2 divisors, whose sum is σ = 18545382. Its totient is φ = 18545380.

The previous prime is 18545363. The next prime is 18545467. The reversal of 18545381 is 18354581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18232900 + 312481 = 4270^2 + 559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18545381 is a prime.

It is a super-2 number, since 2×18545381² = 687862312870322, which contains 22 as substring.

It is equal to p_1183859 and since 18545381 and 1183859 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18545321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9272690 + 9272691.

It is an arithmetic number, because the mean of its divisors is an integer number (9272691).

Almost surely, 2^18545381 is an apocalyptic number.

It is an amenable number.

18545381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18545381 is an equidigital number, since it uses as much as digits as its factorization.

18545381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19200, while the sum is 35.

The square root of 18545381 is about 4306.4348363815. The cubic root of 18545381 is about 264.6947047839.

The spelling of 18545381 in words is "eighteen million, five hundred forty-five thousand, three hundred eighty-one".