13866721 has 6 divisors (see below), whose sum is σ = 15242066. Its totient is φ = 12606000.

The previous prime is 13866691. The next prime is 13866757. The reversal of 13866721 is 12766831.

It can be written as a sum of positive squares in only one way, i.e., 12006225 + 1860496 = 3465^2 + 1364^2 .

It is not a de Polignac number, because 13866721 - 2⁵ = 13866689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13866221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 57180 + ... + 57421.

Almost surely, 2^13866721 is an apocalyptic number.

13866721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13866721 is a deficient number, since it is larger than the sum of its proper divisors (1375345).

13866721 is a wasteful number, since it uses less digits than its factorization.

13866721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114623 (or 114612 counting only the distinct ones).

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

The square root of 13866721 is about 3723.8046404182. The cubic root of 13866721 is about 240.2469737719.

The spelling of 13866721 in words is "thirteen million, eight hundred sixty-six thousand, seven hundred twenty-one".