21352417 has 2 divisors, whose sum is σ = 21352418. Its totient is φ = 21352416.

The previous prime is 21352403. The next prime is 21352421. The reversal of 21352417 is 71425312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19395216 + 1957201 = 4404^2 + 1399^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21352417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21352391 and 21352400.

It is not a weakly prime, because it can be changed into another prime (21352477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676208 + 10676209.

It is an arithmetic number, because the mean of its divisors is an integer number (10676209).

Almost surely, 2^21352417 is an apocalyptic number.

It is an amenable number.

21352417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352417 is an equidigital number, since it uses as much as digits as its factorization.

21352417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 21352417 is about 4620.8675592360. The cubic root of 21352417 is about 277.4271843146.

Adding to 21352417 its reverse (71425312), we get a palindrome (92777729).

The spelling of 21352417 in words is "twenty-one million, three hundred fifty-two thousand, four hundred seventeen".