1211621666 has 8 divisors (see below), whose sum is σ = 1817617260. Its totient is φ = 605749248.

The previous prime is 1211621629. The next prime is 1211621681. The reversal of 1211621666 is 6661261121.

It can be written as a sum of positive squares in 2 ways, for example, as 1185356041 + 26265625 = 34429^2 + 5125^2 .

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 71 + ... + 49226.

Almost surely, 2^1211621666 is an apocalyptic number.

1211621666 is a deficient number, since it is larger than the sum of its proper divisors (605995594).

1211621666 is a wasteful number, since it uses less digits than its factorization.

1211621666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61588.

The product of its digits is 5184, while the sum is 32.

The square root of 1211621666 is about 34808.3562668506. The cubic root of 1211621666 is about 1066.0780713401.

Adding to 1211621666 its reverse (6661261121), we get a palindrome (7872882787).

The spelling of 1211621666 in words is "one billion, two hundred eleven million, six hundred twenty-one thousand, six hundred sixty-six".