221111311021 has 4 divisors (see below), whose sum is σ = 221190197632. Its totient is φ = 221032424412.

The previous prime is 221111311009. The next prime is 221111311027. The reversal of 221111311021 is 120113111122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221111311021 - 2¹⁵ = 221111278253 is a prime.

It is a super-2 number, since 2×221111311021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221111310986 and 221111311004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221111311027) 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, 39439101 + ... + 39444706.

It is an arithmetic number, because the mean of its divisors is an integer number (55297549408).

Almost surely, 2^221111311021 is an apocalyptic number.

It is an amenable number.

221111311021 is a deficient number, since it is larger than the sum of its proper divisors (78886611).

221111311021 is an equidigital number, since it uses as much as digits as its factorization.

221111311021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78886610.

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 221111311021 its reverse (120113111122), we get a palindrome (341224422143).

The spelling of 221111311021 in words is "two hundred twenty-one billion, one hundred eleven million, three hundred eleven thousand, twenty-one".