21427013 has 2 divisors, whose sum is σ = 21427014. Its totient is φ = 21427012.

The previous prime is 21426997. The next prime is 21427037. The reversal of 21427013 is 31072412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20593444 + 833569 = 4538^2 + 913^2 .

It is a cyclic number.

It is not a de Polignac number, because 21427013 - 2⁴ = 21426997 is a prime.

It is a super-2 number, since 2×21427013² = 918233772204338, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21427073) 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, 10713506 + 10713507.

It is an arithmetic number, because the mean of its divisors is an integer number (10713507).

Almost surely, 2^21427013 is an apocalyptic number.

It is an amenable number.

21427013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21427013 is an equidigital number, since it uses as much as digits as its factorization.

21427013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21427013 is about 4628.9321662777. The cubic root of 21427013 is about 277.7498785432.

Adding to 21427013 its reverse (31072412), we get a palindrome (52499425).

The spelling of 21427013 in words is "twenty-one million, four hundred twenty-seven thousand, thirteen".