17981969 has 2 divisors, whose sum is σ = 17981970. Its totient is φ = 17981968.

The previous prime is 17981959. The next prime is 17981981. The reversal of 17981969 is 96918971.

17981969 is nontrivially palindromic in base 16.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 3655744 = 3785^2 + 1912^2 .

It is an emirp because it is prime and its reverse (96918971) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 17981969 - 2⁸ = 17981713 is a prime.

It is a super-2 number, since 2×17981969² = 646702418233922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (17981959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8990984 + 8990985.

It is an arithmetic number, because the mean of its divisors is an integer number (8990985).

Almost surely, 2^17981969 is an apocalyptic number.

It is an amenable number.

17981969 is a deficient number, since it is larger than the sum of its proper divisors (1).

17981969 is an equidigital number, since it uses as much as digits as its factorization.

17981969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 50.

The square root of 17981969 is about 4240.5151809656. The cubic root of 17981969 is about 261.9866016884.

The spelling of 17981969 in words is "seventeen million, nine hundred eighty-one thousand, nine hundred sixty-nine".