16209573561 has 48 divisors (see below), whose sum is σ = 24395507136. Its totient is φ = 10364070528.

The previous prime is 16209573553. The next prime is 16209573581. The reversal of 16209573561 is 16537590261.

16209573561 is a `hidden beast` number, since 1 + 6 + 20 + 9 + 573 + 56 + 1 = 666.

It is not a de Polignac number, because 16209573561 - 2³ = 16209573553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16209573581) 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 47 ways as a sum of consecutive naturals, for example, 5555475 + ... + 5558391.

It is an arithmetic number, because the mean of its divisors is an integer number (508239732).

Almost surely, 2^16209573561 is an apocalyptic number.

It is an amenable number.

16209573561 is a deficient number, since it is larger than the sum of its proper divisors (8185933575).

16209573561 is a wasteful number, since it uses less digits than its factorization.

16209573561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3222 (or 3219 counting only the distinct ones).

The product of its (nonzero) digits is 340200, while the sum is 45.

The spelling of 16209573561 in words is "sixteen billion, two hundred nine million, five hundred seventy-three thousand, five hundred sixty-one".