1661217 has 8 divisors (see below), whose sum is σ = 2229696. Its totient is φ = 1100112.

The previous prime is 1661173. The next prime is 1661237. The reversal of 1661217 is 7121661.

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

It is not a de Polignac number, because 1661217 - 2¹¹ = 1659169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661237) 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, 1293 + ... + 2234.

It is an arithmetic number, because the mean of its divisors is an integer number (278712).

2^1661217 is an apocalyptic number.

It is an amenable number.

1661217 is a deficient number, since it is larger than the sum of its proper divisors (568479).

1661217 is a wasteful number, since it uses less digits than its factorization.

1661217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3687.

The product of its digits is 504, while the sum is 24.

The square root of 1661217 is about 1288.8820737368. The cubic root of 1661217 is about 118.4337431598.

Adding to 1661217 its reverse (7121661), we get a palindrome (8782878).

The spelling of 1661217 in words is "one million, six hundred sixty-one thousand, two hundred seventeen".