1331857728 has 84 divisors (see below), whose sum is σ = 3958965920. Its totient is φ = 443947392.

The previous prime is 1331857727. The next prime is 1331857733. The reversal of 1331857728 is 8277581331.

It is a super-4 number, since 4×1331857728⁴ (a number of 38 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331857721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27268 + ... + 58371.

Almost surely, 2^1331857728 is an apocalyptic number.

1331857728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1331857728 is an abundant number, since it is smaller than the sum of its proper divisors (2627108192).

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

1331857728 is an frugal number, since it uses more digits than its factorization.

1331857728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85666 (or 85644 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The square root of 1331857728 is about 36494.6260153464. The cubic root of 1331857728 is about 1100.2362379667.

The spelling of 1331857728 in words is "one billion, three hundred thirty-one million, eight hundred fifty-seven thousand, seven hundred twenty-eight".