21170217 has 8 divisors (see below), whose sum is σ = 28369600. Its totient is φ = 14042160.

The previous prime is 21170213. The next prime is 21170221. The reversal of 21170217 is 71207112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21170213) and next prime (21170221).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21170217 - 2² = 21170213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21170193 and 21170202.

It is not an unprimeable number, because it can be changed into a prime (21170213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17134 + ... + 18327.

It is an arithmetic number, because the mean of its divisors is an integer number (3546200).

Almost surely, 2^21170217 is an apocalyptic number.

It is an amenable number.

21170217 is a deficient number, since it is larger than the sum of its proper divisors (7199383).

21170217 is a wasteful number, since it uses less digits than its factorization.

21170217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35663.

The product of its (nonzero) digits is 196, while the sum is 21.

The square root of 21170217 is about 4601.1104094555. The cubic root of 21170217 is about 276.6358345345.

Adding to 21170217 its reverse (71207112), we get a palindrome (92377329).

The spelling of 21170217 in words is "twenty-one million, one hundred seventy thousand, two hundred seventeen".