21243011 has 2 divisors, whose sum is σ = 21243012. Its totient is φ = 21243010.

The previous prime is 21242999. The next prime is 21243023. The reversal of 21243011 is 11034212.

It is a balanced prime because it is at equal distance from previous prime (21242999) and next prime (21243023).

It is a cyclic number.

It is not a de Polignac number, because 21243011 - 2¹⁴ = 21226627 is a prime.

It is a super-2 number, since 2×21243011² = 902531032692242, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21243611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621505 + 10621506.

It is an arithmetic number, because the mean of its divisors is an integer number (10621506).

Almost surely, 2^21243011 is an apocalyptic number.

21243011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243011 is an equidigital number, since it uses as much as digits as its factorization.

21243011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21243011 is about 4609.0141028207. The cubic root of 21243011 is about 276.9525434911.

Adding to 21243011 its reverse (11034212), we get a palindrome (32277223).

The spelling of 21243011 in words is "twenty-one million, two hundred forty-three thousand, eleven".