16573406506621 has 4 divisors (see below), whose sum is σ = 16744266367612. Its totient is φ = 16402546645632.

The previous prime is 16573406506609. The next prime is 16573406506627. The reversal of 16573406506621 is 12660560437561.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11525610813721 + 5047795692900 = 3394939^2 + 2246730^2 .

It is a cyclic number.

It is not a de Polignac number, because 16573406506621 - 2⁹ = 16573406506109 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 (16573406506627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85429930350 + ... + 85429930543.

It is an arithmetic number, because the mean of its divisors is an integer number (4186066591903).

Almost surely, 2^{16573406506621} is an apocalyptic number.

It is an amenable number.

16573406506621 is a deficient number, since it is larger than the sum of its proper divisors (170859860991).

16573406506621 is an equidigital number, since it uses as much as digits as its factorization.

16573406506621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170859860990.

The product of its (nonzero) digits is 5443200, while the sum is 52.

The spelling of 16573406506621 in words is "sixteen trillion, five hundred seventy-three billion, four hundred six million, five hundred six thousand, six hundred twenty-one".