21552401302561 has 2 divisors, whose sum is σ = 21552401302562. Its totient is φ = 21552401302560.

The previous prime is 21552401302517. The next prime is 21552401302583. The reversal of 21552401302561 is 16520310425512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20227326350400 + 1325074952161 = 4497480^2 + 1151119^2 .

It is a cyclic number.

It is not a de Polignac number, because 21552401302561 - 2⁴¹ = 19353378047009 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21552401302561.

It is not a weakly prime, because it can be changed into another prime (21552401302961) 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 as a sum of consecutive naturals, namely, 10776200651280 + 10776200651281.

It is an arithmetic number, because the mean of its divisors is an integer number (10776200651281).

Almost surely, 2^{21552401302561} is an apocalyptic number.

It is an amenable number.

21552401302561 is a deficient number, since it is larger than the sum of its proper divisors (1).

21552401302561 is an equidigital number, since it uses as much as digits as its factorization.

21552401302561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72000, while the sum is 37.

The spelling of 21552401302561 in words is "twenty-one trillion, five hundred fifty-two billion, four hundred one million, three hundred two thousand, five hundred sixty-one".