221021020 has 36 divisors (see below), whose sum is σ = 510180552. Its totient is φ = 80370400.

The previous prime is 221020957. The next prime is 221021033. The reversal of 221021020 is 20120122.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 221020988 and 221021006.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43246 + ... + 48085.

It is an arithmetic number, because the mean of its divisors is an integer number (14171682).

Almost surely, 2^221021020 is an apocalyptic number.

221021020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221021020 is an abundant number, since it is smaller than the sum of its proper divisors (289159532).

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

221021020 is a wasteful number, since it uses less digits than its factorization.

221021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91362 (or 91349 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 221021020 is about 14866.7757096150. The cubic root of 221021020 is about 604.6135272793.

Adding to 221021020 its reverse (20120122), we get a palindrome (241141142).

The spelling of 221021020 in words is "two hundred twenty-one million, twenty-one thousand, twenty".