16489981 has 2 divisors, whose sum is σ = 16489982. Its totient is φ = 16489980.

The previous prime is 16489937. The next prime is 16489999. The reversal of 16489981 is 18998461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14212900 + 2277081 = 3770^2 + 1509^2 .

It is a cyclic number.

It is not a de Polignac number, because 16489981 - 2⁹ = 16489469 is a prime.

It is a super-2 number, since 2×16489981² = 543838946760722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16489181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8244990 + 8244991.

It is an arithmetic number, because the mean of its divisors is an integer number (8244991).

Almost surely, 2^16489981 is an apocalyptic number.

It is an amenable number.

16489981 is a deficient number, since it is larger than the sum of its proper divisors (1).

16489981 is an equidigital number, since it uses as much as digits as its factorization.

16489981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 46.

The square root of 16489981 is about 4060.7857614014. The cubic root of 16489981 is about 254.5306295904.

The spelling of 16489981 in words is "sixteen million, four hundred eighty-nine thousand, nine hundred eighty-one".