12171380 has 48 divisors (see below), whose sum is σ = 27788880. Its totient is φ = 4477824.

The previous prime is 12171361. The next prime is 12171389. The reversal of 12171380 is 8317121.

12171380 = T₈₁ + T₈₂ + ... + T₄₁₈.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10797796 + 1373584 = 3286^2 + 1172^2 .

It is a super-2 number, since 2×12171380² = 296284982208800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12171389) 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 15 ways as a sum of consecutive naturals, for example, 43802 + ... + 44078.

It is an arithmetic number, because the mean of its divisors is an integer number (578935).

Almost surely, 2^12171380 is an apocalyptic number.

12171380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12171380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13894440).

12171380 is an abundant number, since it is smaller than the sum of its proper divisors (15617500).

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

12171380 is a wasteful number, since it uses less digits than its factorization.

12171380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 12171380 is about 3488.7504926549. The cubic root of 12171380 is about 230.0275959327.

The spelling of 12171380 in words is "twelve million, one hundred seventy-one thousand, three hundred eighty".