12561905 has 8 divisors (see below), whose sum is σ = 15244200. Its totient is φ = 9936256.

The previous prime is 12561889. The next prime is 12561911. The reversal of 12561905 is 50916521.

It can be written as a sum of positive squares in 4 ways, for example, as 339889 + 12222016 = 583^2 + 3496^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12561905 - 2⁴ = 12561889 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13670 + ... + 14559.

It is an arithmetic number, because the mean of its divisors is an integer number (1905525).

Almost surely, 2^12561905 is an apocalyptic number.

It is an amenable number.

12561905 is a deficient number, since it is larger than the sum of its proper divisors (2682295).

12561905 is an equidigital number, since it uses as much as digits as its factorization.

12561905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28323.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 12561905 is about 3544.2777825673. The cubic root of 12561905 is about 232.4619277082.

The spelling of 12561905 in words is "twelve million, five hundred sixty-one thousand, nine hundred five".