13609681 has 4 divisors (see below), whose sum is σ = 14326000. Its totient is φ = 12893364.

The previous prime is 13609669. The next prime is 13609691. The reversal of 13609681 is 18690631.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18690631 = 47 ⋅397673.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13609681 is a prime.

It is a super-2 number, since 2×13609681² = 370446833843522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (13609601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 358131 + ... + 358168.

It is an arithmetic number, because the mean of its divisors is an integer number (3581500).

Almost surely, 2^13609681 is an apocalyptic number.

It is an amenable number.

13609681 is a deficient number, since it is larger than the sum of its proper divisors (716319).

13609681 is an equidigital number, since it uses as much as digits as its factorization.

13609681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716318.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 13609681 is about 3689.1301142681. The cubic root of 13609681 is about 238.7532627497.

The spelling of 13609681 in words is "thirteen million, six hundred nine thousand, six hundred eighty-one".