1221717 has 12 divisors (see below), whose sum is σ = 1895136. Its totient is φ = 698040.

The previous prime is 1221707. The next prime is 1221749. The reversal of 1221717 is 7171221.

It is a happy number.

It is not a de Polignac number, because 1221717 - 2⁶ = 1221653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

1221717 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1221693 and 1221702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221707) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4009 + ... + 4302.

It is an arithmetic number, because the mean of its divisors is an integer number (157928).

2^1221717 is an apocalyptic number.

It is an amenable number.

1221717 is a deficient number, since it is larger than the sum of its proper divisors (673419).

1221717 is an equidigital number, since it uses as much as digits as its factorization.

1221717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8328 (or 8321 counting only the distinct ones).

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

The square root of 1221717 is about 1105.3130778200. The cubic root of 1221717 is about 106.9030769911.

Adding to 1221717 its reverse (7171221), we get a palindrome (8392938).

The spelling of 1221717 in words is "one million, two hundred twenty-one thousand, seven hundred seventeen".