221801011 has 4 divisors (see below), whose sum is σ = 222161112. Its totient is φ = 221440912.

The previous prime is 221800993. The next prime is 221801059. The reversal of 221801011 is 110108122.

221801011 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 221801011 - 2⁵ = 221800979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221801071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179125 + ... + 180358.

It is an arithmetic number, because the mean of its divisors is an integer number (55540278).

Almost surely, 2^221801011 is an apocalyptic number.

221801011 is a deficient number, since it is larger than the sum of its proper divisors (360101).

221801011 is an equidigital number, since it uses as much as digits as its factorization.

221801011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360100.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 221801011 is about 14892.9852950978. The cubic root of 221801011 is about 605.3239264359.

Adding to 221801011 its reverse (110108122), we get a palindrome (331909133).

The spelling of 221801011 in words is "two hundred twenty-one million, eight hundred one thousand, eleven".