221000211221 has 8 divisors (see below), whose sum is σ = 223336475544. Its totient is φ = 218665128960.

The previous prime is 221000211181. The next prime is 221000211253. The reversal of 221000211221 is 122112000122.

It can be written as a sum of positive squares in 4 ways, for example, as 35679432100 + 185320779121 = 188890^2 + 430489^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-221000211221 is a prime.

It is a super-2 number, since 2×221000211221² (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 = 221000211196 and 221000211205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221000211281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82931 + ... + 669983.

It is an arithmetic number, because the mean of its divisors is an integer number (27917059443).

Almost surely, 2^221000211221 is an apocalyptic number.

It is an amenable number.

221000211221 is a deficient number, since it is larger than the sum of its proper divisors (2336264323).

221000211221 is an equidigital number, since it uses as much as digits as its factorization.

221000211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 591031.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 221000211221 its reverse (122112000122), we get a palindrome (343112211343).

The spelling of 221000211221 in words is "two hundred twenty-one billion, two hundred eleven thousand, two hundred twenty-one".