1668349728 has 36 divisors (see below), whose sum is σ = 4744370358. Its totient is φ = 556116480.

The previous prime is 1668349703. The next prime is 1668349759. The reversal of 1668349728 is 8279438661.

It can be written as a sum of positive squares in only one way, i.e., 1271065104 + 397284624 = 35652^2 + 19932^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2896153 + ... + 2896728.

Almost surely, 2^1668349728 is an apocalyptic number.

1668349728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1668349728 is an abundant number, since it is smaller than the sum of its proper divisors (3076020630).

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

1668349728 is a wasteful number, since it uses less digits than its factorization.

1668349728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5792897 (or 5792886 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 54.

The square root of 1668349728 is about 40845.4370523808. The cubic root of 1668349728 is about 1186.0300652032.

The spelling of 1668349728 in words is "one billion, six hundred sixty-eight million, three hundred forty-nine thousand, seven hundred twenty-eight".