13097781 has 20 divisors (see below), whose sum is σ = 19771884. Its totient is φ = 8640000.

The previous prime is 13097771. The next prime is 13097797. The reversal of 13097781 is 18779031.

It can be written as a sum of positive squares in 2 ways, for example, as 12895281 + 202500 = 3591^2 + 450^2 .

It is not a de Polignac number, because 13097781 - 2⁷ = 13097653 is a prime.

It is a super-2 number, since 2×13097781² = 343103734247922, which contains 22 as substring.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13097761) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7381 + ... + 8981.

Almost surely, 2^13097781 is an apocalyptic number.

It is an amenable number.

13097781 is a deficient number, since it is larger than the sum of its proper divisors (6674103).

13097781 is a wasteful number, since it uses less digits than its factorization.

13097781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1714 (or 1705 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 13097781 is about 3619.0856580081. The cubic root of 13097781 is about 235.7215246891.

The spelling of 13097781 in words is "thirteen million, ninety-seven thousand, seven hundred eighty-one".