21360217 has 4 divisors (see below), whose sum is σ = 21384576. Its totient is φ = 21335860.

The previous prime is 21360197. The next prime is 21360223. The reversal of 21360217 is 71206312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21360217 - 2¹⁹ = 20835929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21360247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10813 + ... + 12634.

It is an arithmetic number, because the mean of its divisors is an integer number (5346144).

Almost surely, 2^21360217 is an apocalyptic number.

It is an amenable number.

21360217 is a deficient number, since it is larger than the sum of its proper divisors (24359).

21360217 is an equidigital number, since it uses as much as digits as its factorization.

21360217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24358.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21360217 is about 4621.7114795279. The cubic root of 21360217 is about 277.4609614212.

Adding to 21360217 its reverse (71206312), we get a palindrome (92566529).

The spelling of 21360217 in words is "twenty-one million, three hundred sixty thousand, two hundred seventeen".