21003413 has 2 divisors, whose sum is σ = 21003414. Its totient is φ = 21003412.

The previous prime is 21003397. The next prime is 21003427. The reversal of 21003413 is 31430012.

It is an a-pointer prime, because the next prime (21003427) can be obtained adding 21003413 to its sum of digits (14).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20857489 + 145924 = 4567^2 + 382^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003413 - 2⁴ = 21003397 is a prime.

It is a super-2 number, since 2×21003413² = 882286715297138, 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 (21003473) 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, 10501706 + 10501707.

It is an arithmetic number, because the mean of its divisors is an integer number (10501707).

Almost surely, 2^21003413 is an apocalyptic number.

It is an amenable number.

21003413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003413 is an equidigital number, since it uses as much as digits as its factorization.

21003413 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 21003413 is about 4582.9480686562. The cubic root of 21003413 is about 275.9073631907.

Adding to 21003413 its reverse (31430012), we get a palindrome (52433425).

The spelling of 21003413 in words is "twenty-one million, three thousand, four hundred thirteen".