1000204921 has 2 divisors, whose sum is σ = 1000204922. Its totient is φ = 1000204920.

The previous prime is 1000204913. The next prime is 1000204981. The reversal of 1000204921 is 1294020001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 608164921 + 392040000 = 24661^2 + 19800^2 .

It is an emirp because it is prime and its reverse (1294020001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1000204921 - 2³ = 1000204913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1000204981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500102460 + 500102461.

It is an arithmetic number, because the mean of its divisors is an integer number (500102461).

Almost surely, 2^1000204921 is an apocalyptic number.

It is an amenable number.

1000204921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000204921 is an equidigital number, since it uses as much as digits as its factorization.

1000204921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 1000204921 is about 31626.0165212124. The cubic root of 1000204921 is about 1000.0683023347.

Adding to 1000204921 its reverse (1294020001), we get a palindrome (2294224922).

The spelling of 1000204921 in words is "one billion, two hundred four thousand, nine hundred twenty-one".