221221212102 has 128 divisors (see below), whose sum is σ = 547743306240. Its totient is φ = 65611728000.

The previous prime is 221221212089. The next prime is 221221212127. The reversal of 221221212102 is 201212122122.

It is a happy number.

221221212102 is a `hidden beast` number, since 221 + 221 + 212 + 10 + 2 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13245577 + ... + 13262267.

It is an arithmetic number, because the mean of its divisors is an integer number (4279244580).

Almost surely, 2^221221212102 is an apocalyptic number.

221221212102 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 221221212102, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273871653120).

221221212102 is an abundant number, since it is smaller than the sum of its proper divisors (326522094138).

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

221221212102 is a wasteful number, since it uses less digits than its factorization.

221221212102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17187 (or 17181 counting only the distinct ones).

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

Adding to 221221212102 its reverse (201212122122), we get a palindrome (422433334224).

The spelling of 221221212102 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred two".