21545203 has 2 divisors, whose sum is σ = 21545204. Its totient is φ = 21545202.

The previous prime is 21545201. The next prime is 21545233. The reversal of 21545203 is 30254512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21545203 - 2¹ = 21545201 is a prime.

It is a super-2 number, since 2×21545203² = 928391544622418, which contains 22 as substring.

Together with 21545201, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21545201) 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, 10772601 + 10772602.

It is an arithmetic number, because the mean of its divisors is an integer number (10772602).

Almost surely, 2^21545203 is an apocalyptic number.

21545203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21545203 is an equidigital number, since it uses as much as digits as its factorization.

21545203 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21545203 is about 4641.6810532392. The cubic root of 21545203 is about 278.2596258227.

Adding to 21545203 its reverse (30254512), we get a palindrome (51799715).

The spelling of 21545203 in words is "twenty-one million, five hundred forty-five thousand, two hundred three".