221001211221 has 16 divisors (see below), whose sum is σ = 336845443200. Its totient is φ = 126255771648.

The previous prime is 221001211217. The next prime is 221001211241. The reversal of 221001211221 is 122112100122.

It is not a de Polignac number, because 221001211221 - 2² = 221001211217 is a prime.

It is a super-3 number, since 3×221001211221³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 221001211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001211241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1187676 + ... + 1361093.

It is an arithmetic number, because the mean of its divisors is an integer number (21052840200).

Almost surely, 2^221001211221 is an apocalyptic number.

221001211221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221001211221 is a deficient number, since it is larger than the sum of its proper divisors (115844231979).

221001211221 is a wasteful number, since it uses less digits than its factorization.

221001211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2552908.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 221001211221 its reverse (122112100122), we get a palindrome (343113311343).

It can be divided in two parts, 22100 and 1211221, that added together give a palindrome (1233321).

The spelling of 221001211221 in words is "two hundred twenty-one billion, one million, two hundred eleven thousand, two hundred twenty-one".