21121003 has 2 divisors, whose sum is σ = 21121004. Its totient is φ = 21121002.

The previous prime is 21120959. The next prime is 21121033. The reversal of 21121003 is 30012112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121003 - 2¹⁷ = 20989931 is a prime.

It is not a weakly prime, because it can be changed into another prime (21121033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560501 + 10560502.

It is an arithmetic number, because the mean of its divisors is an integer number (10560502).

Almost surely, 2^21121003 is an apocalyptic number.

21121003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121003 is an equidigital number, since it uses as much as digits as its factorization.

21121003 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21121003 is about 4595.7592408654. The cubic root of 21121003 is about 276.4213048600.

Adding to 21121003 its reverse (30012112), we get a palindrome (51133115).

The spelling of 21121003 in words is "twenty-one million, one hundred twenty-one thousand, three".