13688781 has 8 divisors (see below), whose sum is σ = 18333024. Its totient is φ = 9085200.

The previous prime is 13688771. The next prime is 13688789. The reversal of 13688781 is 18788631.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13688781 - 2¹⁴ = 13672397 is a prime.

It is a super-2 number, since 2×13688781² = 374765450531922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13688789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9370 + ... + 10731.

It is an arithmetic number, because the mean of its divisors is an integer number (2291628).

Almost surely, 2^13688781 is an apocalyptic number.

It is an amenable number.

13688781 is a deficient number, since it is larger than the sum of its proper divisors (4644243).

13688781 is a wasteful number, since it uses less digits than its factorization.

13688781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20331.

The product of its digits is 64512, while the sum is 42.

The square root of 13688781 is about 3699.8352666031. The cubic root of 13688781 is about 239.2149172939.

The spelling of 13688781 in words is "thirteen million, six hundred eighty-eight thousand, seven hundred eighty-one".