13389781 has 2 divisors, whose sum is σ = 13389782. Its totient is φ = 13389780.

The previous prime is 13389773. The next prime is 13389787. The reversal of 13389781 is 18798331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7672900 + 5716881 = 2770^2 + 2391^2 .

It is a cyclic number.

It is not a de Polignac number, because 13389781 - 2³ = 13389773 is a prime.

It is a super-2 number, since 2×13389781² = 358572470455922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13389787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6694890 + 6694891.

It is an arithmetic number, because the mean of its divisors is an integer number (6694891).

Almost surely, 2^13389781 is an apocalyptic number.

It is an amenable number.

13389781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13389781 is an equidigital number, since it uses as much as digits as its factorization.

13389781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 40.

The square root of 13389781 is about 3659.2049682957. The cubic root of 13389781 is about 237.4603797251.

The spelling of 13389781 in words is "thirteen million, three hundred eighty-nine thousand, seven hundred eighty-one".