15601242221 has 2 divisors, whose sum is σ = 15601242222. Its totient is φ = 15601242220.

The previous prime is 15601242203. The next prime is 15601242269. The reversal of 15601242221 is 12224210651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11840486596 + 3760755625 = 108814^2 + 61325^2 .

It is a cyclic number.

It is not a de Polignac number, because 15601242221 - 2¹⁸ = 15600980077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15601242271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7800621110 + 7800621111.

It is an arithmetic number, because the mean of its divisors is an integer number (7800621111).

Almost surely, 2^15601242221 is an apocalyptic number.

It is an amenable number.

15601242221 is a deficient number, since it is larger than the sum of its proper divisors (1).

15601242221 is an equidigital number, since it uses as much as digits as its factorization.

15601242221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

Adding to 15601242221 its reverse (12224210651), we get a palindrome (27825452872).

The spelling of 15601242221 in words is "fifteen billion, six hundred one million, two hundred forty-two thousand, two hundred twenty-one".