21573803 has 2 divisors, whose sum is σ = 21573804. Its totient is φ = 21573802.

The previous prime is 21573791. The next prime is 21573829. The reversal of 21573803 is 30837512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21573803 - 2⁴ = 21573787 is a prime.

It is not a weakly prime, because it can be changed into another prime (21573863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10786901 + 10786902.

It is an arithmetic number, because the mean of its divisors is an integer number (10786902).

Almost surely, 2^21573803 is an apocalyptic number.

21573803 is a deficient number, since it is larger than the sum of its proper divisors (1).

21573803 is an equidigital number, since it uses as much as digits as its factorization.

21573803 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21573803 is about 4644.7608119256. The cubic root of 21573803 is about 278.3826958558.

The spelling of 21573803 in words is "twenty-one million, five hundred seventy-three thousand, eight hundred three".