221690811 has 4 divisors (see below), whose sum is σ = 295587752. Its totient is φ = 147793872.

The previous prime is 221690783. The next prime is 221690851. The reversal of 221690811 is 118096122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 221690811 - 2⁵ = 221690779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221690851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36948466 + ... + 36948471.

It is an arithmetic number, because the mean of its divisors is an integer number (73896938).

Almost surely, 2^221690811 is an apocalyptic number.

221690811 is a deficient number, since it is larger than the sum of its proper divisors (73896941).

221690811 is an equidigital number, since it uses as much as digits as its factorization.

221690811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73896940.

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 221690811 is about 14889.2851070829. The cubic root of 221690811 is about 605.2236597644.

The spelling of 221690811 in words is "two hundred twenty-one million, six hundred ninety thousand, eight hundred eleven".