13667981 has 2 divisors, whose sum is σ = 13667982. Its totient is φ = 13667980.

The previous prime is 13667977. The next prime is 13667987. The reversal of 13667981 is 18976631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12145225 + 1522756 = 3485^2 + 1234^2 .

It is a cyclic number.

It is not a de Polignac number, because 13667981 - 2² = 13667977 is a prime.

It is a super-2 number, since 2×13667981² = 373627409232722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13667987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6833990 + 6833991.

It is an arithmetic number, because the mean of its divisors is an integer number (6833991).

Almost surely, 2^13667981 is an apocalyptic number.

It is an amenable number.

13667981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13667981 is an equidigital number, since it uses as much as digits as its factorization.

13667981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 41.

The square root of 13667981 is about 3697.0232620312. The cubic root of 13667981 is about 239.0936941168.

The spelling of 13667981 in words is "thirteen million, six hundred sixty-seven thousand, nine hundred eighty-one".