16728016681 has 2 divisors, whose sum is σ = 16728016682. Its totient is φ = 16728016680.

The previous prime is 16728016637. The next prime is 16728016717. The reversal of 16728016681 is 18661082761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13667714281 + 3060302400 = 116909^2 + 55320^2 .

It is a cyclic number.

It is not a de Polignac number, because 16728016681 - 2⁹ = 16728016169 is a prime.

It is a super-2 number, since 2×16728016681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16728016621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8364008340 + 8364008341.

It is an arithmetic number, because the mean of its divisors is an integer number (8364008341).

Almost surely, 2^16728016681 is an apocalyptic number.

It is an amenable number.

16728016681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16728016681 is an equidigital number, since it uses as much as digits as its factorization.

16728016681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 46.

The spelling of 16728016681 in words is "sixteen billion, seven hundred twenty-eight million, sixteen thousand, six hundred eighty-one".