1328909681 has 8 divisors (see below), whose sum is σ = 1458402624.
Its totient is φ = 1200863920.
The previous prime is 1328909633. The next prime is 1328909689. The reversal of 1328909681 is 1869098231.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is not a de Polignac number, because 1328909681 - 210 = 1328908657 is a prime.
It is a super-2 number, since 2×13289096812 = 3532001880511043522, which contains 22 as substring.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (1328909689) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 359870 + ... + 363543.
It is an arithmetic number, because the mean of its divisors is an integer number (182300328).
Almost surely, 21328909681 is an apocalyptic number.
1328909681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.
It is an amenable number.
1328909681 is a deficient number, since it is larger than the sum of its proper divisors (129492943).
1328909681 is a wasteful number, since it uses less digits than its factorization.
1328909681 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 723591.
The product of its (nonzero) digits is 186624, while the sum is 47.
The square root of 1328909681 is about 36454.2134876066.
The cubic root of 1328909681 is about 1099.4238528294.
The spelling of 1328909681 in words is "one billion, three hundred twenty-eight million, nine hundred nine thousand, six hundred eighty-one".