13530781 has 4 divisors (see below), whose sum is σ = 14760864. Its totient is φ = 12300700.

The previous prime is 13530763. The next prime is 13530809. The reversal of 13530781 is 18703531.

13530781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13530781 - 2⁷ = 13530653 is a prime.

It is a super-2 number, since 2×13530781² = 366164068939922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13530701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 615025 + ... + 615046.

It is an arithmetic number, because the mean of its divisors is an integer number (3690216).

Almost surely, 2^13530781 is an apocalyptic number.

13530781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13530781 is a deficient number, since it is larger than the sum of its proper divisors (1230083).

13530781 is a wasteful number, since it uses less digits than its factorization.

13530781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1230082.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 13530781 is about 3678.4209927631. The cubic root of 13530781 is about 238.2909900270.

The spelling of 13530781 in words is "thirteen million, five hundred thirty thousand, seven hundred eighty-one".