6211221665 has 16 divisors (see below), whose sum is σ = 8205658560. Its totient is φ = 4475805120.

The previous prime is 6211221647. The next prime is 6211221673. The reversal of 6211221665 is 5661221126.

It is not a de Polignac number, because 6211221665 - 2¹² = 6211217569 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 512039 + ... + 524028.

It is an arithmetic number, because the mean of its divisors is an integer number (512853660).

Almost surely, 2^6211221665 is an apocalyptic number.

It is an amenable number.

6211221665 is a deficient number, since it is larger than the sum of its proper divisors (1994436895).

6211221665 is a wasteful number, since it uses less digits than its factorization.

6211221665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1036192.

The product of its digits is 8640, while the sum is 32.

The square root of 6211221665 is about 78811.3041701506. The cubic root of 6211221665 is about 1838.1982268821.

The spelling of 6211221665 in words is "six billion, two hundred eleven million, two hundred twenty-one thousand, six hundred sixty-five".