6211806561 has 12 divisors (see below), whose sum is σ = 9018158292. Its totient is φ = 4120181856.

The previous prime is 6211806551. The next prime is 6211806607. The reversal of 6211806561 is 1656081126.

6211806561 is a `hidden beast` number, since 6 + 2 + 11 + 80 + 6 + 561 = 666.

6211806561 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 6149696400 + 62110161 = 78420^2 + 7881^2 .

It is not a de Polignac number, because 6211806561 - 2²³ = 6203417953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6211806521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1750006 + ... + 1753551.

It is an arithmetic number, because the mean of its divisors is an integer number (751513191).

Almost surely, 2^6211806561 is an apocalyptic number.

It is an amenable number.

6211806561 is a deficient number, since it is larger than the sum of its proper divisors (2806351731).

6211806561 is a wasteful number, since it uses less digits than its factorization.

6211806561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3503760 (or 3503757 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 6211806561 is about 78815.0148195127. The cubic root of 6211806561 is about 1838.2559246589.

Adding to 6211806561 its reverse (1656081126), we get a palindrome (7867887687).

The spelling of 6211806561 in words is "six billion, two hundred eleven million, eight hundred six thousand, five hundred sixty-one".