21308003 has 2 divisors, whose sum is σ = 21308004. Its totient is φ = 21308002.

The previous prime is 21307999. The next prime is 21308017. The reversal of 21308003 is 30080312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21308003 - 2² = 21307999 is a prime.

It is not a weakly prime, because it can be changed into another prime (21308303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10654001 + 10654002.

It is an arithmetic number, because the mean of its divisors is an integer number (10654002).

Almost surely, 2^21308003 is an apocalyptic number.

21308003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21308003 is an equidigital number, since it uses as much as digits as its factorization.

21308003 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 17.

The square root of 21308003 is about 4616.0592500530. The cubic root of 21308003 is about 277.2346970652.

Adding to 21308003 its reverse (30080312), we get a palindrome (51388315).

The spelling of 21308003 in words is "twenty-one million, three hundred eight thousand, three".