12561462221 has 32 divisors (see below), whose sum is σ = 15769141248. Its totient is φ = 9720829440.

The previous prime is 12561462211. The next prime is 12561462227. The reversal of 12561462221 is 12226416521.

It is not a de Polignac number, because 12561462221 - 2¹⁸ = 12561200077 is a prime.

It is a super-2 number, since 2×12561462221² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12561462227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11555540 + ... + 11556626.

It is an arithmetic number, because the mean of its divisors is an integer number (492785664).

Almost surely, 2^12561462221 is an apocalyptic number.

12561462221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12561462221 is a deficient number, since it is larger than the sum of its proper divisors (3207679027).

12561462221 is a wasteful number, since it uses less digits than its factorization.

12561462221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2001.

The product of its digits is 11520, while the sum is 32.

Adding to 12561462221 its reverse (12226416521), we get a palindrome (24787878742).

The spelling of 12561462221 in words is "twelve billion, five hundred sixty-one million, four hundred sixty-two thousand, two hundred twenty-one".