21356003 has 2 divisors, whose sum is σ = 21356004. Its totient is φ = 21356002.

The previous prime is 21355987. The next prime is 21356047. The reversal of 21356003 is 30065312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21356003 - 2⁴ = 21355987 is a prime.

It is not a weakly prime, because it can be changed into another prime (21356603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678001 + 10678002.

It is an arithmetic number, because the mean of its divisors is an integer number (10678002).

Almost surely, 2^21356003 is an apocalyptic number.

21356003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21356003 is an equidigital number, since it uses as much as digits as its factorization.

21356003 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 21356003 is about 4621.2555653199. The cubic root of 21356003 is about 277.4427141442.

The spelling of 21356003 in words is "twenty-one million, three hundred fifty-six thousand, three".