18231481 has 2 divisors, whose sum is σ = 18231482. Its totient is φ = 18231480.

The previous prime is 18231467. The next prime is 18231509. The reversal of 18231481 is 18413281.

It is an a-pointer prime, because the next prime (18231509) can be obtained adding 18231481 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16646400 + 1585081 = 4080^2 + 1259^2 .

It is an emirp because it is prime and its reverse (18413281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18231481 - 2⁹ = 18230969 is a prime.

It is a super-2 number, since 2×18231481² = 664773798906722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18231461) 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 as a sum of consecutive naturals, namely, 9115740 + 9115741.

It is an arithmetic number, because the mean of its divisors is an integer number (9115741).

Almost surely, 2^18231481 is an apocalyptic number.

It is an amenable number.

18231481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18231481 is an equidigital number, since it uses as much as digits as its factorization.

18231481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1536, while the sum is 28.

The square root of 18231481 is about 4269.8338375164. The cubic root of 18231481 is about 263.1927870780.

The spelling of 18231481 in words is "eighteen million, two hundred thirty-one thousand, four hundred eighty-one".