221220717 has 8 divisors (see below), whose sum is σ = 296109696. Its totient is φ = 146906112.

The previous prime is 221220697. The next prime is 221220737. The reversal of 221220717 is 717022122.

It is an interprime number because it is at equal distance from previous prime (221220697) and next prime (221220737).

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

It is not a de Polignac number, because 221220717 - 2⁷ = 221220589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221220737) 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, 142693 + ... + 144234.

It is an arithmetic number, because the mean of its divisors is an integer number (37013712).

Almost surely, 2^221220717 is an apocalyptic number.

It is an amenable number.

221220717 is a deficient number, since it is larger than the sum of its proper divisors (74888979).

221220717 is a wasteful number, since it uses less digits than its factorization.

221220717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287187.

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 221220717 is about 14873.4904107946. The cubic root of 221220717 is about 604.7955660167.

Adding to 221220717 its reverse (717022122), we get a palindrome (938242839).

The spelling of 221220717 in words is "two hundred twenty-one million, two hundred twenty thousand, seven hundred seventeen".