16628681 has 2 divisors, whose sum is σ = 16628682. Its totient is φ = 16628680.

The previous prime is 16628653. The next prime is 16628693. The reversal of 16628681 is 18682661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13075456 + 3553225 = 3616^2 + 1885^2 .

It is an emirp because it is prime and its reverse (18682661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16628681 is a prime.

It is a super-2 number, since 2×16628681² = 553026063599522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16628641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8314340 + 8314341.

It is an arithmetic number, because the mean of its divisors is an integer number (8314341).

Almost surely, 2^16628681 is an apocalyptic number.

It is an amenable number.

16628681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16628681 is an equidigital number, since it uses as much as digits as its factorization.

16628681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 38.

The square root of 16628681 is about 4077.8279757734. The cubic root of 16628681 is about 255.2422713510.

The spelling of 16628681 in words is "sixteen million, six hundred twenty-eight thousand, six hundred eighty-one".