1000021221 has 20 divisors (see below), whose sum is σ = 1494828192. Its totient is φ = 666248328.

The previous prime is 1000021193. The next prime is 1000021229. The reversal of 1000021221 is 1221200001.

It is not a de Polignac number, because 1000021221 - 2⁵ = 1000021189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

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

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 165760 + ... + 171686.

Almost surely, 2^1000021221 is an apocalyptic number.

It is an amenable number.

1000021221 is a deficient number, since it is larger than the sum of its proper divisors (494806971).

1000021221 is an equidigital number, since it uses as much as digits as its factorization.

1000021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8022 (or 8013 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1000021221 is about 31623.1121333749. The cubic root of 1000021221 is about 1000.0070736166.

Adding to 1000021221 its reverse (1221200001), we get a palindrome (2221221222).

The spelling of 1000021221 in words is "one billion, twenty-one thousand, two hundred twenty-one".