16554403982521 has 2 divisors, whose sum is σ = 16554403982522. Its totient is φ = 16554403982520.

The previous prime is 16554403982471. The next prime is 16554403982533. The reversal of 16554403982521 is 12528930445561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16372705542400 + 181698440121 = 4046320^2 + 426261^2 .

It is a cyclic number.

It is not a de Polignac number, because 16554403982521 - 2¹⁵ = 16554403949753 is a prime.

It is not a weakly prime, because it can be changed into another prime (16554403982581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8277201991260 + 8277201991261.

It is an arithmetic number, because the mean of its divisors is an integer number (8277201991261).

Almost surely, 2^{16554403982521} is an apocalyptic number.

It is an amenable number.

16554403982521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16554403982521 is an equidigital number, since it uses as much as digits as its factorization.

16554403982521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368000, while the sum is 55.

The spelling of 16554403982521 in words is "sixteen trillion, five hundred fifty-four billion, four hundred three million, nine hundred eighty-two thousand, five hundred twenty-one".