12221952561 has 24 divisors (see below), whose sum is σ = 21727917120. Its totient is φ = 6446743776.

The previous prime is 12221952551. The next prime is 12221952563. The reversal of 12221952561 is 16525912221.

12221952561 is a `hidden beast` number, since 1 + 2 + 2 + 2 + 1 + 95 + 2 + 561 = 666.

It is not a de Polignac number, because 12221952561 - 2⁵ = 12221952529 is a prime.

It is a super-2 number, since 2×12221952561² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12221952563) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7460691 + ... + 7462328.

It is an arithmetic number, because the mean of its divisors is an integer number (905329880).

Almost surely, 2^12221952561 is an apocalyptic number.

It is an amenable number.

12221952561 is a deficient number, since it is larger than the sum of its proper divisors (9505964559).

12221952561 is a wasteful number, since it uses less digits than its factorization.

12221952561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14923045 (or 14923042 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The spelling of 12221952561 in words is "twelve billion, two hundred twenty-one million, nine hundred fifty-two thousand, five hundred sixty-one".