13009781 has 2 divisors, whose sum is σ = 13009782. Its totient is φ = 13009780.

The previous prime is 13009771. The next prime is 13009807. The reversal of 13009781 is 18790031.

13009781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9891025 + 3118756 = 3145^2 + 1766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13009781 is a prime.

It is a super-2 number, since 2×13009781² = 338508803335922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13009721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6504890 + 6504891.

It is an arithmetic number, because the mean of its divisors is an integer number (6504891).

Almost surely, 2^13009781 is an apocalyptic number.

It is an amenable number.

13009781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13009781 is an equidigital number, since it uses as much as digits as its factorization.

13009781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 29.

The square root of 13009781 is about 3606.9074010848. The cubic root of 13009781 is about 235.1924242570.

The spelling of 13009781 in words is "thirteen million, nine thousand, seven hundred eighty-one".