13457981 has 4 divisors (see below), whose sum is σ = 13478652. Its totient is φ = 13437312.

The previous prime is 13457971. The next prime is 13457987. The reversal of 13457981 is 18975431.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8323225 + 5134756 = 2885^2 + 2266^2 .

It is a cyclic number.

It is not a de Polignac number, because 13457981 - 2¹⁸ = 13195837 is a prime.

It is a super-2 number, since 2×13457981² = 362234505192722, 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 (13457987) 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, 9326 + ... + 10671.

It is an arithmetic number, because the mean of its divisors is an integer number (3369663).

Almost surely, 2^13457981 is an apocalyptic number.

It is an amenable number.

13457981 is a deficient number, since it is larger than the sum of its proper divisors (20671).

13457981 is an equidigital number, since it uses as much as digits as its factorization.

13457981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20670.

The product of its digits is 30240, while the sum is 38.

The square root of 13457981 is about 3668.5120962047. The cubic root of 13457981 is about 237.8628602863.

The spelling of 13457981 in words is "thirteen million, four hundred fifty-seven thousand, nine hundred eighty-one".