206091187561 has 8 divisors (see below), whose sum is σ = 249387655680. Its totient is φ = 166258436928.

The previous prime is 206091187559. The next prime is 206091187607. The reversal of 206091187561 is 165781190602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 206091187561 - 2¹ = 206091187559 is a prime.

It is a super-2 number, since 2×206091187561² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206091187661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 865929241 + ... + 865929478.

It is an arithmetic number, because the mean of its divisors is an integer number (31173456960).

Almost surely, 2^206091187561 is an apocalyptic number.

It is an amenable number.

206091187561 is a deficient number, since it is larger than the sum of its proper divisors (43296468119).

206091187561 is a wasteful number, since it uses less digits than its factorization.

206091187561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731858743.

The product of its (nonzero) digits is 181440, while the sum is 46.

The spelling of 206091187561 in words is "two hundred six billion, ninety-one million, one hundred eighty-seven thousand, five hundred sixty-one".