21070217 has 8 divisors (see below), whose sum is σ = 24151296. Its totient is φ = 18006912.

The previous prime is 21070201. The next prime is 21070237. The reversal of 21070217 is 71207012.

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

It is not a de Polignac number, because 21070217 - 2⁴ = 21070201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21070237) 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, 1793 + ... + 6734.

It is an arithmetic number, because the mean of its divisors is an integer number (3018912).

Almost surely, 2^21070217 is an apocalyptic number.

It is an amenable number.

21070217 is a deficient number, since it is larger than the sum of its proper divisors (3081079).

21070217 is an equidigital number, since it uses as much as digits as its factorization.

21070217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8887.

The product of its (nonzero) digits is 196, while the sum is 20.

The square root of 21070217 is about 4590.2306042289. The cubic root of 21070217 is about 276.1995729772.

Adding to 21070217 its reverse (71207012), we get a palindrome (92277229).

The spelling of 21070217 in words is "twenty-one million, seventy thousand, two hundred seventeen".