21000461 has 2 divisors, whose sum is σ = 21000462. Its totient is φ = 21000460.

The previous prime is 21000433. The next prime is 21000467. The reversal of 21000461 is 16400012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16859236 + 4141225 = 4106^2 + 2035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000461 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000467) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500230 + 10500231.

It is an arithmetic number, because the mean of its divisors is an integer number (10500231).

Almost surely, 2^21000461 is an apocalyptic number.

It is an amenable number.

21000461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000461 is an equidigital number, since it uses as much as digits as its factorization.

21000461 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21000461 is about 4582.6259939035. The cubic root of 21000461 is about 275.8944364552.

Adding to 21000461 its reverse (16400012), we get a palindrome (37400473).

The spelling of 21000461 in words is "twenty-one million, four hundred sixty-one", and thus it is an aban number.