221231011 has 4 divisors (see below), whose sum is σ = 222149224. Its totient is φ = 220312800.

The previous prime is 221231009. The next prime is 221231027. The reversal of 221231011 is 110132122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 110132122 = 2 ⋅55066061.

It is a cyclic number.

It is not a de Polignac number, because 221231011 - 2¹ = 221231009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221230982 and 221231000.

It is not an unprimeable number, because it can be changed into a prime (221261011) 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, 458745 + ... + 459226.

It is an arithmetic number, because the mean of its divisors is an integer number (55537306).

Almost surely, 2^221231011 is an apocalyptic number.

221231011 is a deficient number, since it is larger than the sum of its proper divisors (918213).

221231011 is an equidigital number, since it uses as much as digits as its factorization.

221231011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918212.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 221231011 is about 14873.8364586948. The cubic root of 221231011 is about 604.8049467972.

Adding to 221231011 its reverse (110132122), we get a palindrome (331363133).

The spelling of 221231011 in words is "two hundred twenty-one million, two hundred thirty-one thousand, eleven".