12171520 has 72 divisors (see below), whose sum is σ = 30059064. Its totient is φ = 4718592.

The previous prime is 12171487. The next prime is 12171527. The reversal of 12171520 is 2517121.

It can be written as a sum of positive squares in 4 ways, for example, as 7225344 + 4946176 = 2688^2 + 2224^2 .

It is a super-2 number, since 2×12171520² = 296291798220800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12171527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47232 + ... + 47488.

It is an arithmetic number, because the mean of its divisors is an integer number (417487).

Almost surely, 2^12171520 is an apocalyptic number.

12171520 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 12171520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15029532).

12171520 is an abundant number, since it is smaller than the sum of its proper divisors (17887544).

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

12171520 is an equidigital number, since it uses as much as digits as its factorization.

12171520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315 (or 301 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 12171520 is about 3488.7705570874. The cubic root of 12171520 is about 230.0284778853.

Adding to 12171520 its reverse (2517121), we get a palindrome (14688641).

The spelling of 12171520 in words is "twelve million, one hundred seventy-one thousand, five hundred twenty".