220121660 has 48 divisors (see below), whose sum is σ = 505945440. Its totient is φ = 79779840.

The previous prime is 220121641. The next prime is 220121663. The reversal of 220121660 is 66121022.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220121663) 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, 72656 + ... + 75624.

It is an arithmetic number, because the mean of its divisors is an integer number (10540530).

Almost surely, 2^220121660 is an apocalyptic number.

220121660 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 220121660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252972720).

220121660 is an abundant number, since it is smaller than the sum of its proper divisors (285823780).

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

220121660 is a wasteful number, since it uses less digits than its factorization.

220121660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3326 (or 3324 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 220121660 is about 14836.4975651263. The cubic root of 220121660 is about 603.7923317183.

Adding to 220121660 its reverse (66121022), we get a palindrome (286242682).

The spelling of 220121660 in words is "two hundred twenty million, one hundred twenty-one thousand, six hundred sixty".