12813981 has 4 divisors (see below), whose sum is σ = 17085312. Its totient is φ = 8542652.

The previous prime is 12813979. The next prime is 12813989. The reversal of 12813981 is 18931821.

12813981 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18931821 = 3 ⋅6310607.

It is a cyclic number.

It is not a de Polignac number, because 12813981 - 2¹ = 12813979 is a prime.

It is a super-2 number, since 2×12813981² = 328396218136722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12813989) 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, 2135661 + ... + 2135666.

It is an arithmetic number, because the mean of its divisors is an integer number (4271328).

Almost surely, 2^12813981 is an apocalyptic number.

It is an amenable number.

12813981 is a deficient number, since it is larger than the sum of its proper divisors (4271331).

12813981 is an equidigital number, since it uses as much as digits as its factorization.

12813981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4271330.

The product of its digits is 3456, while the sum is 33.

The square root of 12813981 is about 3579.6621348949. The cubic root of 12813981 is about 234.0065561754.

The spelling of 12813981 in words is "twelve million, eight hundred thirteen thousand, nine hundred eighty-one".