221672066891 has 32 divisors (see below), whose sum is σ = 263746022400. Its totient is φ = 184109345280.

The previous prime is 221672066881. The next prime is 221672066893. The reversal of 221672066891 is 198660276122.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221672066891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221672066893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 746990 + ... + 1000668.

It is an arithmetic number, because the mean of its divisors is an integer number (8242063200).

Almost surely, 2^221672066891 is an apocalyptic number.

221672066891 is a deficient number, since it is larger than the sum of its proper divisors (42073955509).

221672066891 is a wasteful number, since it uses less digits than its factorization.

221672066891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253859.

The product of its (nonzero) digits is 870912, while the sum is 50.

The spelling of 221672066891 in words is "two hundred twenty-one billion, six hundred seventy-two million, sixty-six thousand, eight hundred ninety-one".