13728661 has 2 divisors, whose sum is σ = 13728662. Its totient is φ = 13728660.

The previous prime is 13728647. The next prime is 13728679. The reversal of 13728661 is 16682731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7128900 + 6599761 = 2670^2 + 2569^2 .

It is a cyclic number.

It is not a de Polignac number, because 13728661 - 2¹¹ = 13726613 is a prime.

It is a super-2 number, since 2×13728661² = 376952265705842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13728461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6864330 + 6864331.

It is an arithmetic number, because the mean of its divisors is an integer number (6864331).

Almost surely, 2^13728661 is an apocalyptic number.

It is an amenable number.

13728661 is a deficient number, since it is larger than the sum of its proper divisors (1).

13728661 is an equidigital number, since it uses as much as digits as its factorization.

13728661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 13728661 is about 3705.2207761482. The cubic root of 13728661 is about 239.4469964340.

The spelling of 13728661 in words is "thirteen million, seven hundred twenty-eight thousand, six hundred sixty-one".