13778681 has 4 divisors (see below), whose sum is σ = 15747072. Its totient is φ = 11810292.

The previous prime is 13778671. The next prime is 13778717. The reversal of 13778681 is 18687731.

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 a de Polignac number, because none of the positive numbers 2^k-13778681 is a prime.

It is a super-2 number, since 2×13778681² = 379704100199522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13778641) 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, 984185 + ... + 984198.

It is an arithmetic number, because the mean of its divisors is an integer number (3936768).

Almost surely, 2^13778681 is an apocalyptic number.

It is an amenable number.

13778681 is a deficient number, since it is larger than the sum of its proper divisors (1968391).

13778681 is an equidigital number, since it uses as much as digits as its factorization.

13778681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1968390.

The product of its digits is 56448, while the sum is 41.

The square root of 13778681 is about 3711.9645741844. The cubic root of 13778681 is about 239.7374501548.

The spelling of 13778681 in words is "thirteen million, seven hundred seventy-eight thousand, six hundred eighty-one".