18140981 has 2 divisors, whose sum is σ = 18140982. Its totient is φ = 18140980.

The previous prime is 18140971. The next prime is 18141031. The reversal of 18140981 is 18904181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13256881 + 4884100 = 3641^2 + 2210^2 .

It is a cyclic number.

It is not a de Polignac number, because 18140981 - 2⁶ = 18140917 is a prime.

It is a super-2 number, since 2×18140981² = 658190383284722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18140971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9070490 + 9070491.

It is an arithmetic number, because the mean of its divisors is an integer number (9070491).

Almost surely, 2^18140981 is an apocalyptic number.

It is an amenable number.

18140981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18140981 is an equidigital number, since it uses as much as digits as its factorization.

18140981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 32.

The square root of 18140981 is about 4259.2230512149. The cubic root of 18140981 is about 262.7565733253.

The spelling of 18140981 in words is "eighteen million, one hundred forty thousand, nine hundred eighty-one".