12891031 has 4 divisors (see below), whose sum is σ = 13134312. Its totient is φ = 12647752.

The previous prime is 12891029. The next prime is 12891037. The reversal of 12891031 is 13019821.

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

It is a cyclic number.

It is not a de Polignac number, because 12891031 - 2¹ = 12891029 is a prime.

It is a super-2 number, since 2×12891031² = 332357360485922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12890987 and 12891005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12891037) 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 in 3 ways as a sum of consecutive naturals, for example, 121561 + ... + 121666.

It is an arithmetic number, because the mean of its divisors is an integer number (3283578).

Almost surely, 2^12891031 is an apocalyptic number.

12891031 is a deficient number, since it is larger than the sum of its proper divisors (243281).

12891031 is an equidigital number, since it uses as much as digits as its factorization.

12891031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243280.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 12891031 is about 3590.4081940637. The cubic root of 12891031 is about 234.4746435214.

The spelling of 12891031 in words is "twelve million, eight hundred ninety-one thousand, thirty-one".