13138981 has 4 divisors (see below), whose sum is σ = 13286700. Its totient is φ = 12991264.

The previous prime is 13138949. The next prime is 13138997. The reversal of 13138981 is 18983131.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18983131 = 137 ⋅138563.

It can be written as a sum of positive squares in 2 ways, for example, as 1809025 + 11329956 = 1345^2 + 3366^2 .

It is a cyclic number.

It is not a de Polignac number, because 13138981 - 2⁵ = 13138949 is a prime.

It is a super-2 number, since 2×13138981² = 345265643436722, 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 (13138381) 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 in 3 ways as a sum of consecutive naturals, for example, 73726 + ... + 73903.

It is an arithmetic number, because the mean of its divisors is an integer number (3321675).

Almost surely, 2^13138981 is an apocalyptic number.

It is an amenable number.

13138981 is a deficient number, since it is larger than the sum of its proper divisors (147719).

13138981 is an equidigital number, since it uses as much as digits as its factorization.

13138981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147718.

The product of its digits is 5184, while the sum is 34.

The square root of 13138981 is about 3624.7732342865. The cubic root of 13138981 is about 235.9684255853.

The spelling of 13138981 in words is "thirteen million, one hundred thirty-eight thousand, nine hundred eighty-one".