12128720 has 20 divisors (see below), whose sum is σ = 28199460. Its totient is φ = 4851456.

The previous prime is 12128713. The next prime is 12128729. The reversal of 12128720 is 2782121.

It can be written as a sum of positive squares in 2 ways, for example, as 6330256 + 5798464 = 2516^2 + 2408^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12128729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75725 + ... + 75884.

It is an arithmetic number, because the mean of its divisors is an integer number (1409973).

Almost surely, 2^12128720 is an apocalyptic number.

12128720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12128720 is an abundant number, since it is smaller than the sum of its proper divisors (16070740).

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

12128720 is a wasteful number, since it uses less digits than its factorization.

12128720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151622 (or 151616 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 12128720 is about 3482.6311892016. The cubic root of 12128720 is about 229.7585367610.

The spelling of 12128720 in words is "twelve million, one hundred twenty-eight thousand, seven hundred twenty".