6621866109 has 12 divisors (see below), whose sum is σ = 9565809916. Its totient is φ = 4414165632.

The previous prime is 6621866059. The next prime is 6621866113. The reversal of 6621866109 is 9016681266.

6621866109 is a `hidden beast` number, since 6 + 6 + 21 + 8 + 6 + 610 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 391921209 + 6229944900 = 19797^2 + 78930^2 .

It is not a de Polignac number, because 6621866109 - 2¹³ = 6621857917 is a prime.

It is a super-2 number, since 2×6621866109² = 87698221531045599762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6621866609) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 92007 + ... + 147339.

Almost surely, 2^6621866109 is an apocalyptic number.

It is an amenable number.

6621866109 is a deficient number, since it is larger than the sum of its proper divisors (2943943807).

6621866109 is a wasteful number, since it uses less digits than its factorization.

6621866109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68636 (or 68633 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 6621866109 is about 81374.8493639159. The cubic root of 6621866109 is about 1877.8466847386.

The spelling of 6621866109 in words is "six billion, six hundred twenty-one million, eight hundred sixty-six thousand, one hundred nine".