12005021561 has 8 divisors (see below), whose sum is σ = 12949379520. Its totient is φ = 11063648592.

The previous prime is 12005021549. The next prime is 12005021599. The reversal of 12005021561 is 16512050021.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12005021561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12005021761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 737885 + ... + 753978.

It is an arithmetic number, because the mean of its divisors is an integer number (1618672440).

Almost surely, 2^12005021561 is an apocalyptic number.

It is an amenable number.

12005021561 is a deficient number, since it is larger than the sum of its proper divisors (944357959).

12005021561 is a wasteful number, since it uses less digits than its factorization.

12005021561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1492495.

The product of its (nonzero) digits is 600, while the sum is 23.

Adding to 12005021561 its reverse (16512050021), we get a palindrome (28517071582).

The spelling of 12005021561 in words is "twelve billion, five million, twenty-one thousand, five hundred sixty-one".