13400665 has 4 divisors (see below), whose sum is σ = 16080804. Its totient is φ = 10720528.

The previous prime is 13400657. The next prime is 13400689. The reversal of 13400665 is 56600431.

13400665 = 2588² + 2589².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56600431 = 29 ⋅1951739.

It can be written as a sum of positive squares in 2 ways, for example, as 6697744 + 6702921 = 2588^2 + 2589^2 .

It is a cyclic number.

It is not a de Polignac number, because 13400665 - 2³ = 13400657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1340062 + ... + 1340071.

It is an arithmetic number, because the mean of its divisors is an integer number (4020201).

Almost surely, 2^13400665 is an apocalyptic number.

13400665 is the 2589-th centered square number.

It is an amenable number.

13400665 is a deficient number, since it is larger than the sum of its proper divisors (2680139).

13400665 is an equidigital number, since it uses as much as digits as its factorization.

13400665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2680138.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 13400665 is about 3660.6918744959. The cubic root of 13400665 is about 237.5247028783.

The spelling of 13400665 in words is "thirteen million, four hundred thousand, six hundred sixty-five".