1000021220 has 24 divisors (see below), whose sum is σ = 2290958208. Its totient is φ = 363644000.

The previous prime is 1000021193. The next prime is 1000021229. The reversal of 1000021220 is 221200001.

It is a junction number, because it is equal to n+sod(n) for n = 1000021198 and 1000021207.

It is not an unprimeable number, because it can be changed into a prime (1000021229) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2272556 + ... + 2272995.

It is an arithmetic number, because the mean of its divisors is an integer number (95456592).

Almost surely, 2^1000021220 is an apocalyptic number.

1000021220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1000021220 is an abundant number, since it is smaller than the sum of its proper divisors (1290936988).

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

1000021220 is a wasteful number, since it uses less digits than its factorization.

1000021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4545571 (or 4545569 counting only the distinct ones).

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

The square root of 1000021220 is about 31623.1121175636. The cubic root of 1000021220 is about 1000.0070732833.

Adding to 1000021220 its reverse (221200001), we get a palindrome (1221221221).

The spelling of 1000021220 in words is "one billion, twenty-one thousand, two hundred twenty".