12561840 has 120 divisors (see below), whose sum is σ = 42943680. Its totient is φ = 3290112.

The previous prime is 12561823. The next prime is 12561859. The reversal of 12561840 is 4816521.

12561840 is a `hidden beast` number, since 1 + 2 + 5 + 618 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52441 + ... + 52679.

It is an arithmetic number, because the mean of its divisors is an integer number (357864).

Almost surely, 2^12561840 is an apocalyptic number.

12561840 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 12561840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21471840).

12561840 is an abundant number, since it is smaller than the sum of its proper divisors (30381840).

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

12561840 is a wasteful number, since it uses less digits than its factorization.

12561840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 12561840 is about 3544.2686128453. The cubic root of 12561840 is about 232.4615267592.

The spelling of 12561840 in words is "twelve million, five hundred sixty-one thousand, eight hundred forty".