1221668 has 36 divisors (see below), whose sum is σ = 2604672. Its totient is φ = 498960.

The previous prime is 1221667. The next prime is 1221707. The reversal of 1221668 is 8661221.

It is not an unprimeable number, because it can be changed into a prime (1221667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4373 + ... + 4643.

It is an arithmetic number, because the mean of its divisors is an integer number (72352).

2^1221668 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1302336).

1221668 is an abundant number, since it is smaller than the sum of its proper divisors (1383004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221668 is a wasteful number, since it uses less digits than its factorization.

1221668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 303 counting only the distinct ones).

The product of its digits is 1152, while the sum is 26.

The square root of 1221668 is about 1105.2909119322. The cubic root of 1221668 is about 106.9016477674.

Adding to 1221668 its reverse (8661221), we get a palindrome (9882889).

The spelling of 1221668 in words is "one million, two hundred twenty-one thousand, six hundred sixty-eight".