13503681 has 6 divisors (see below), whose sum is σ = 19505330. Its totient is φ = 9002448.

The previous prime is 13503673. The next prime is 13503709. The reversal of 13503681 is 18630531.

It can be written as a sum of positive squares in only one way, i.e., 12895281 + 608400 = 3591^2 + 780^2 .

It is not a de Polignac number, because 13503681 - 2³ = 13503673 is a prime.

It is a super-2 number, since 2×13503681² = 364698801099522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13503601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 750196 + ... + 750213.

Almost surely, 2^13503681 is an apocalyptic number.

It is an amenable number.

13503681 is a deficient number, since it is larger than the sum of its proper divisors (6001649).

13503681 is a wasteful number, since it uses less digits than its factorization.

13503681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1500415 (or 1500412 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 13503681 is about 3674.7355006857. The cubic root of 13503681 is about 238.1317973962.

The spelling of 13503681 in words is "thirteen million, five hundred three thousand, six hundred eighty-one".