21415417 has 2 divisors, whose sum is σ = 21415418. Its totient is φ = 21415416.

The previous prime is 21415379. The next prime is 21415423. The reversal of 21415417 is 71451412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11861136 + 9554281 = 3444^2 + 3091^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415417 - 2¹¹ = 21413369 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21415391 and 21415400.

It is not a weakly prime, because it can be changed into another prime (21415217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707708 + 10707709.

It is an arithmetic number, because the mean of its divisors is an integer number (10707709).

Almost surely, 2^21415417 is an apocalyptic number.

It is an amenable number.

21415417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415417 is an equidigital number, since it uses as much as digits as its factorization.

21415417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1120, while the sum is 25.

The square root of 21415417 is about 4627.6794400650. The cubic root of 21415417 is about 277.6997647175.

Adding to 21415417 its reverse (71451412), we get a palindrome (92866829).

The spelling of 21415417 in words is "twenty-one million, four hundred fifteen thousand, four hundred seventeen".