221020 has 24 divisors (see below), whose sum is σ = 476784. Its totient is φ = 86016.

The previous prime is 220973. The next prime is 221021. The reversal of 221020 is 20122.

It is a happy number.

221020 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 220994 and 221012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221021) by changing a digit.

221020 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 732 + ... + 988.

It is an arithmetic number, because the mean of its divisors is an integer number (19866).

2²²¹⁰²⁰ is an apocalyptic number.

221020 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 221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238392).

221020 is an abundant number, since it is smaller than the sum of its proper divisors (255764).

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

221020 is a wasteful number, since it uses less digits than its factorization.

221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 221020 is about 470.1276422420. The cubic root of 221020 is about 60.4612597192.

Adding to 221020 its reverse (20122), we get a palindrome (241142).

The spelling of 221020 in words is "two hundred twenty-one thousand, twenty", and thus it is an iban number.