13000781 has 2 divisors, whose sum is σ = 13000782. Its totient is φ = 13000780.

The previous prime is 13000753. The next prime is 13000829. The reversal of 13000781 is 18700031.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9424900 + 3575881 = 3070^2 + 1891^2 .

It is a cyclic number.

It is not a de Polignac number, because 13000781 - 2¹⁸ = 12738637 is a prime.

It is a super-2 number, since 2×13000781² = 338040613219922, 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 (13000711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6500390 + 6500391.

It is an arithmetic number, because the mean of its divisors is an integer number (6500391).

Almost surely, 2^13000781 is an apocalyptic number.

13000781 is the 1613-rd centered decagonal number.

It is an amenable number.

13000781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13000781 is an equidigital number, since it uses as much as digits as its factorization.

13000781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 13000781 is about 3605.6595790507. The cubic root of 13000781 is about 235.1381773762.

The spelling of 13000781 in words is "thirteen million, seven hundred eighty-one", and thus it is an aban number.