21003011 has 2 divisors, whose sum is σ = 21003012. Its totient is φ = 21003010.

The previous prime is 21003001. The next prime is 21003053. The reversal of 21003011 is 11030012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21003011 is a prime.

It is a super-2 number, since 2×21003011² = 882252942132242, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21003011.

It is not a weakly prime, because it can be changed into another prime (21003001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501505 + 10501506.

It is an arithmetic number, because the mean of its divisors is an integer number (10501506).

Almost surely, 2^21003011 is an apocalyptic number.

21003011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003011 is an equidigital number, since it uses as much as digits as its factorization.

21003011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6, while the sum is 8.

The square root of 21003011 is about 4582.9042102143. The cubic root of 21003011 is about 275.9056029138.

Adding to 21003011 its reverse (11030012), we get a palindrome (32033023).

The spelling of 21003011 in words is "twenty-one million, three thousand, eleven".