12891640 has 32 divisors (see below), whose sum is σ = 29302560. Its totient is φ = 5104000.

The previous prime is 12891623. The next prime is 12891647. The reversal of 12891640 is 4619821.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12891647) 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 7 ways as a sum of consecutive naturals, for example, 2445 + ... + 5635.

It is an arithmetic number, because the mean of its divisors is an integer number (915705).

Almost surely, 2^12891640 is an apocalyptic number.

12891640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12891640 is an abundant number, since it is smaller than the sum of its proper divisors (16410920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12891640 is a wasteful number, since it uses less digits than its factorization.

12891640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3303 (or 3299 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 12891640 is about 3590.4930023605. The cubic root of 12891640 is about 234.4783358252.

It can be divided in two parts, 12891 and 640, that added together give a palindrome (13531).

The spelling of 12891640 in words is "twelve million, eight hundred ninety-one thousand, six hundred forty".