13608781 has 4 divisors (see below), whose sum is σ = 13620672. Its totient is φ = 13596892.

The previous prime is 13608779. The next prime is 13608787. The reversal of 13608781 is 18780631.

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: 18780631 = 17 ⋅1104743.

It is a cyclic number.

It is not a de Polignac number, because 13608781 - 2¹ = 13608779 is a prime.

It is a super-2 number, since 2×13608781² = 370397840611922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13608787) 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, 4021 + ... + 6586.

It is an arithmetic number, because the mean of its divisors is an integer number (3405168).

Almost surely, 2^13608781 is an apocalyptic number.

It is an amenable number.

13608781 is a deficient number, since it is larger than the sum of its proper divisors (11891).

13608781 is a wasteful number, since it uses less digits than its factorization.

13608781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11890.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 13608781 is about 3689.0081322762. The cubic root of 13608781 is about 238.7479997639.

The spelling of 13608781 in words is "thirteen million, six hundred eight thousand, seven hundred eighty-one".