21004579 has 2 divisors, whose sum is σ = 21004580. Its totient is φ = 21004578.

The previous prime is 21004549. The next prime is 21004583. The reversal of 21004579 is 97540012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21004579 - 2⁵ = 21004547 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502289 + 10502290.

It is an arithmetic number, because the mean of its divisors is an integer number (10502290).

Almost surely, 2^21004579 is an apocalyptic number.

21004579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004579 is an equidigital number, since it uses as much as digits as its factorization.

21004579 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21004579 is about 4583.0752775838. The cubic root of 21004579 is about 275.9124687424.

The spelling of 21004579 in words is "twenty-one million, four thousand, five hundred seventy-nine".