17981881 has 2 divisors, whose sum is σ = 17981882. Its totient is φ = 17981880.

The previous prime is 17981857. The next prime is 17981917. The reversal of 17981881 is 18818971.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17935225 + 46656 = 4235^2 + 216^2 .

It is a cyclic number.

It is not a de Polignac number, because 17981881 - 2⁵ = 17981849 is a prime.

It is a super-2 number, since 2×17981881² = 646696088596322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (17981851) 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, 8990940 + 8990941.

It is an arithmetic number, because the mean of its divisors is an integer number (8990941).

Almost surely, 2^17981881 is an apocalyptic number.

It is an amenable number.

17981881 is a deficient number, since it is larger than the sum of its proper divisors (1).

17981881 is an equidigital number, since it uses as much as digits as its factorization.

17981881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 43.

The square root of 17981881 is about 4240.5048048552. The cubic root of 17981881 is about 261.9861743185.

The spelling of 17981881 in words is "seventeen million, nine hundred eighty-one thousand, eight hundred eighty-one".