12221542521 has 10 divisors (see below), whose sum is σ = 18256872282. Its totient is φ = 8147694960.

The previous prime is 12221542519. The next prime is 12221542589. The reversal of 12221542521 is 12524512221.

12221542521 is a `hidden beast` number, since 1 + 2 + 2 + 215 + 425 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 10859932521 + 1361610000 = 104211^2 + 36900^2 .

It is not a de Polignac number, because 12221542521 - 2¹ = 12221542519 is a prime.

It is a super-2 number, since 2×12221542521² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (12221542621) 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 9 ways as a sum of consecutive naturals, for example, 75441540 + ... + 75441701.

Almost surely, 2^12221542521 is an apocalyptic number.

It is an amenable number.

12221542521 is a deficient number, since it is larger than the sum of its proper divisors (6035329761).

12221542521 is an equidigital number, since it uses as much as digits as its factorization.

12221542521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150883253 (or 150883244 counting only the distinct ones).

The product of its digits is 3200, while the sum is 27.

The spelling of 12221542521 in words is "twelve billion, two hundred twenty-one million, five hundred forty-two thousand, five hundred twenty-one".