21016417 has 2 divisors, whose sum is σ = 21016418. Its totient is φ = 21016416.

The previous prime is 21016409. The next prime is 21016423. The reversal of 21016417 is 71461012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19501056 + 1515361 = 4416^2 + 1231^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016417 - 2³ = 21016409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21016427) 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, 10508208 + 10508209.

It is an arithmetic number, because the mean of its divisors is an integer number (10508209).

Almost surely, 2^21016417 is an apocalyptic number.

It is an amenable number.

21016417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21016417 is an equidigital number, since it uses as much as digits as its factorization.

21016417 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 22.

The square root of 21016417 is about 4584.3665865635. The cubic root of 21016417 is about 275.9642929722.

Adding to 21016417 its reverse (71461012), we get a palindrome (92477429).

The spelling of 21016417 in words is "twenty-one million, sixteen thousand, four hundred seventeen".