1217728 has 28 divisors (see below), whose sum is σ = 2468880. Its totient is φ = 595712.

The previous prime is 1217719. The next prime is 1217731. The reversal of 1217728 is 8277121.

It is a super-2 number, since 2×1217728² = 2965722963968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1217696 and 1217705.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 3213 + ... + 3571.

2^1217728 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 1217728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1234440).

1217728 is an abundant number, since it is smaller than the sum of its proper divisors (1251152).

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

1217728 is an equidigital number, since it uses as much as digits as its factorization.

1217728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424 (or 414 counting only the distinct ones).

The product of its digits is 1568, while the sum is 28.

The square root of 1217728 is about 1103.5071363612. The cubic root of 1217728 is about 106.7866012078.

The spelling of 1217728 in words is "one million, two hundred seventeen thousand, seven hundred twenty-eight".