221210121020 has 96 divisors (see below), whose sum is σ = 562322331648. Its totient is φ = 71358170112.

The previous prime is 221210121019. The next prime is 221210121059. The reversal of 221210121020 is 20121012122.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 221210120986 and 221210121004.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 7942439 + ... + 7970241.

It is an arithmetic number, because the mean of its divisors is an integer number (5857524288).

Almost surely, 2^221210121020 is an apocalyptic number.

221210121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221210121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (281161165824).

221210121020 is an abundant number, since it is smaller than the sum of its proper divisors (341112210628).

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

221210121020 is a wasteful number, since it uses less digits than its factorization.

221210121020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31179 (or 31177 counting only the distinct ones).

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

Adding to 221210121020 its reverse (20121012122), we get a palindrome (241331133142).

The spelling of 221210121020 in words is "two hundred twenty-one billion, two hundred ten million, one hundred twenty-one thousand, twenty".