133657728 has 64 divisors (see below), whose sum is σ = 357873120. Its totient is φ = 44195840.

The previous prime is 133657703. The next prime is 133657793. The reversal of 133657728 is 827756331.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 133657728.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48976 + ... + 51632.

Almost surely, 2^133657728 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 133657728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178936560).

133657728 is an abundant number, since it is smaller than the sum of its proper divisors (224215392).

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

133657728 is a wasteful number, since it uses less digits than its factorization.

133657728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2805 (or 2793 counting only the distinct ones).

The product of its digits is 211680, while the sum is 42.

The square root of 133657728 is about 11561.0435515139. The cubic root of 133657728 is about 511.2869305364.

The spelling of 133657728 in words is "one hundred thirty-three million, six hundred fifty-seven thousand, seven hundred twenty-eight".