1220665 has 8 divisors (see below), whose sum is σ = 1472328. Its totient is φ = 971520.

The previous prime is 1220663. The next prime is 1220669. The reversal of 1220665 is 5660221.

It can be written as a sum of positive squares in 4 ways, for example, as 8464 + 1212201 = 92^2 + 1101^2 .

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

It is not a de Polignac number, because 1220665 - 2¹ = 1220663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220663) 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, 699 + ... + 1711.

It is an arithmetic number, because the mean of its divisors is an integer number (184041).

2^1220665 is an apocalyptic number.

It is an amenable number.

1220665 is a deficient number, since it is larger than the sum of its proper divisors (251663).

1220665 is a wasteful number, since it uses less digits than its factorization.

1220665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1259.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1220665 is about 1104.8370920638. The cubic root of 1220665 is about 106.8723840314.

Adding to 1220665 its reverse (5660221), we get a palindrome (6880886).

The spelling of 1220665 in words is "one million, two hundred twenty thousand, six hundred sixty-five".