16564645557541 has 4 divisors (see below), whose sum is σ = 16564680386284. Its totient is φ = 16564610728800.

The previous prime is 16564645557529. The next prime is 16564645557553. The reversal of 16564645557541 is 14575554646561.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (16564645557529) and next prime (16564645557553).

It can be written as a sum of positive squares in 2 ways, for example, as 6709503853441 + 9855141704100 = 2590271^2 + 3139290^2 .

It is a cyclic number.

It is not a de Polignac number, because 16564645557541 - 2¹⁵ = 16564645524773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16564645557521) 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 3 ways as a sum of consecutive naturals, for example, 16690950 + ... + 17655511.

It is an arithmetic number, because the mean of its divisors is an integer number (4141170096571).

Almost surely, 2^{16564645557541} is an apocalyptic number.

It is an amenable number.

16564645557541 is a deficient number, since it is larger than the sum of its proper divisors (34828743).

16564645557541 is an equidigital number, since it uses as much as digits as its factorization.

16564645557541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34828742.

The product of its digits is 302400000, while the sum is 64.

The spelling of 16564645557541 in words is "sixteen trillion, five hundred sixty-four billion, six hundred forty-five million, five hundred fifty-seven thousand, five hundred forty-one".