13863781 has 4 divisors (see below), whose sum is σ = 14201964. Its totient is φ = 13525600.

The previous prime is 13863767. The next prime is 13863791. The reversal of 13863781 is 18736831.

13863781 = 370² + 371² + ... + 451².

13863781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18736831 = 19 ⋅986149.

It can be written as a sum of positive squares in 2 ways, for example, as 5832225 + 8031556 = 2415^2 + 2834^2 .

It is a cyclic number.

It is not a de Polignac number, because 13863781 - 2¹¹ = 13861733 is a prime.

It is a super-2 number, since 2×13863781² = 384408847231922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13863781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13863791) 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 3 ways as a sum of consecutive naturals, for example, 169030 + ... + 169111.

It is an arithmetic number, because the mean of its divisors is an integer number (3550491).

Almost surely, 2^13863781 is an apocalyptic number.

It is an amenable number.

13863781 is a deficient number, since it is larger than the sum of its proper divisors (338183).

13863781 is an equidigital number, since it uses as much as digits as its factorization.

13863781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338182.

The product of its digits is 24192, while the sum is 37.

The square root of 13863781 is about 3723.4098619411. The cubic root of 13863781 is about 240.2299936455.

The spelling of 13863781 in words is "thirteen million, eight hundred sixty-three thousand, seven hundred eighty-one".