1329664 has 60 divisors (see below), whose sum is σ = 3148794. Its totient is φ = 559104.

The previous prime is 1329661. The next prime is 1329673. The reversal of 1329664 is 4669231.

It can be written as a sum of positive squares in only one way, i.e., 1016064 + 313600 = 1008^2 + 560^2 .

It is not an unprimeable number, because it can be changed into a prime (1329661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25062 + ... + 25114.

2^1329664 is an apocalyptic number.

1329664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1329664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1574397).

1329664 is an abundant number, since it is smaller than the sum of its proper divisors (1819130).

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

1329664 is an frugal number, since it uses more digits than its factorization.

1329664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 62 counting only the distinct ones).

The product of its digits is 7776, while the sum is 31.

The square root of 1329664 is about 1153.1105757905. The cubic root of 1329664 is about 109.9631832712.

It can be divided in two parts, 1329 and 664, that multiplied together give a triangular number (882456 = T₁₃₂₈).

The spelling of 1329664 in words is "one million, three hundred twenty-nine thousand, six hundred sixty-four".