1000021209 has 96 divisors (see below), whose sum is σ = 1663635456. Its totient is φ = 528506880.

The previous prime is 1000021193. The next prime is 1000021229. The reversal of 1000021209 is 9021200001.

It is a happy number.

It is not a de Polignac number, because 1000021209 - 2⁴ = 1000021193 is a prime.

It is a Curzon 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 95 ways as a sum of consecutive naturals, for example, 10309449 + ... + 10309545.

It is an arithmetic number, because the mean of its divisors is an integer number (17329536).

Almost surely, 2^1000021209 is an apocalyptic number.

It is an amenable number.

1000021209 is a deficient number, since it is larger than the sum of its proper divisors (663614247).

1000021209 is a wasteful number, since it uses less digits than its factorization.

1000021209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 1000021209 is about 31623.1119436402. Note that the first 3 decimals coincide. The cubic root of 1000021209 is about 1000.0070696167.

The spelling of 1000021209 in words is "one billion, twenty-one thousand, two hundred nine".