21403013 has 2 divisors, whose sum is σ = 21403014. Its totient is φ = 21403012.

The previous prime is 21402977. The next prime is 21403033. The reversal of 21403013 is 31030412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20448484 + 954529 = 4522^2 + 977^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403013 - 2¹² = 21398917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21403033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701506 + 10701507.

It is an arithmetic number, because the mean of its divisors is an integer number (10701507).

Almost surely, 2^21403013 is an apocalyptic number.

It is an amenable number.

21403013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403013 is an equidigital number, since it uses as much as digits as its factorization.

21403013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21403013 is about 4626.3390493996. The cubic root of 21403013 is about 277.6461389714.

Adding to 21403013 its reverse (31030412), we get a palindrome (52433425).

The spelling of 21403013 in words is "twenty-one million, four hundred three thousand, thirteen".