13936781 has 4 divisors (see below), whose sum is σ = 14542752. Its totient is φ = 13330812.

The previous prime is 13936771. The next prime is 13936799. The reversal of 13936781 is 18763931.

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: 18763931 = 137 ⋅136963.

It is a cyclic number.

It is not a de Polignac number, because 13936781 - 2¹⁸ = 13674637 is a prime.

It is a super-2 number, since 2×13936781² = 388467729283922, 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 (13936771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 302951 + ... + 302996.

It is an arithmetic number, because the mean of its divisors is an integer number (3635688).

Almost surely, 2^13936781 is an apocalyptic number.

It is an amenable number.

13936781 is a deficient number, since it is larger than the sum of its proper divisors (605971).

13936781 is an equidigital number, since it uses as much as digits as its factorization.

13936781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605970.

The product of its digits is 27216, while the sum is 38.

The square root of 13936781 is about 3733.1998339226. The cubic root of 13936781 is about 240.6509009281.

The spelling of 13936781 in words is "thirteen million, nine hundred thirty-six thousand, seven hundred eighty-one".