13549981 has 2 divisors, whose sum is σ = 13549982. Its totient is φ = 13549980.

The previous prime is 13549973. The next prime is 13550039. The reversal of 13549981 is 18994531.

13549981 is nontrivially palindromic in base 15.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12320100 + 1229881 = 3510^2 + 1109^2 .

It is a cyclic number.

It is not a de Polignac number, because 13549981 - 2³ = 13549973 is a prime.

It is a super-2 number, since 2×13549981² = 367203970200722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13549961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6774990 + 6774991.

It is an arithmetic number, because the mean of its divisors is an integer number (6774991).

Almost surely, 2^13549981 is an apocalyptic number.

It is an amenable number.

13549981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13549981 is an equidigital number, since it uses as much as digits as its factorization.

13549981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 40.

The square root of 13549981 is about 3681.0298830626. The cubic root of 13549981 is about 238.4036473493.

The spelling of 13549981 in words is "thirteen million, five hundred forty-nine thousand, nine hundred eighty-one".