221221012122 has 48 divisors (see below), whose sum is σ = 535639366080. Its totient is φ = 65401627200.

The previous prime is 221221012063. The next prime is 221221012169. The reversal of 221221012122 is 221210122122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 221221012095 and 221221012104.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13617222 + ... + 13633457.

It is an arithmetic number, because the mean of its divisors is an integer number (11159153460).

Almost surely, 2^221221012122 is an apocalyptic number.

221221012122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

221221012122 is an abundant number, since it is smaller than the sum of its proper divisors (314418353958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221221012122 is a wasteful number, since it uses less digits than its factorization.

221221012122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27250739 (or 27250736 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 221221012122 its reverse (221210122122), we get a palindrome (442431134244).

Subtracting from 221221012122 its reverse (221210122122), we obtain a square (10890000 = 3300²).

The spelling of 221221012122 in words is "two hundred twenty-one billion, two hundred twenty-one million, twelve thousand, one hundred twenty-two".