16388681 has 2 divisors, whose sum is σ = 16388682. Its totient is φ = 16388680.

The previous prime is 16388641. The next prime is 16388693. The reversal of 16388681 is 18688361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16321600 + 67081 = 4040^2 + 259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16388681 is a prime.

It is a super-2 number, since 2×16388681² = 537177729839522, which contains 22 as substring.

It is a Chen prime.

It is a nialpdrome in base 8.

It is not a weakly prime, because it can be changed into another prime (16388641) 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, 8194340 + 8194341.

It is an arithmetic number, because the mean of its divisors is an integer number (8194341).

Almost surely, 2^16388681 is an apocalyptic number.

It is an amenable number.

16388681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16388681 is an equidigital number, since it uses as much as digits as its factorization.

16388681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 41.

The square root of 16388681 is about 4048.2935911319. The cubic root of 16388681 is about 254.0083542419.

The spelling of 16388681 in words is "sixteen million, three hundred eighty-eight thousand, six hundred eighty-one".