13243781 has 4 divisors (see below), whose sum is σ = 13339200. Its totient is φ = 13148364.

The previous prime is 13243777. The next prime is 13243793. The reversal of 13243781 is 18734231.

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.

It is a cyclic number.

It is not a de Polignac number, because 13243781 - 2² = 13243777 is a prime.

It is a super-2 number, since 2×13243781² = 350795470351922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13243751) 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, 47501 + ... + 47778.

It is an arithmetic number, because the mean of its divisors is an integer number (3334800).

Almost surely, 2^13243781 is an apocalyptic number.

13243781 is the 1628-th centered decagonal number.

It is an amenable number.

13243781 is a deficient number, since it is larger than the sum of its proper divisors (95419).

13243781 is an equidigital number, since it uses as much as digits as its factorization.

13243781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95418.

The product of its digits is 4032, while the sum is 29.

The square root of 13243781 is about 3639.2005990327. The cubic root of 13243781 is about 236.5941471476.

The spelling of 13243781 in words is "thirteen million, two hundred forty-three thousand, seven hundred eighty-one".