12691890 has 56 divisors (see below), whose sum is σ = 34272108. Its totient is φ = 3382560.

The previous prime is 12691871. The next prime is 12691891. The reversal of 12691890 is 9819621.

It can be written as a sum of positive squares in 2 ways, for example, as 10323369 + 2368521 = 3213^2 + 1539^2 .

It is a super-3 number, since 3×12691890³ (a number of 22 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (12691891) 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 27 ways as a sum of consecutive naturals, for example, 6420 + ... + 8160.

Almost surely, 2^12691890 is an apocalyptic number.

12691890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12691890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17136054).

12691890 is an abundant number, since it is smaller than the sum of its proper divisors (21580218).

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

12691890 is an equidigital number, since it uses as much as digits as its factorization.

12691890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1751 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 12691890 is about 3562.5678940899. The cubic root of 12691890 is about 233.2609821030.

The spelling of 12691890 in words is "twelve million, six hundred ninety-one thousand, eight hundred ninety".