133681536 has 128 divisors (see below), whose sum is σ = 403430400. Its totient is φ = 43559424.

The previous prime is 133681519. The next prime is 133681547. The reversal of 133681536 is 635186331.

It is a happy number.

133681536 is a `hidden beast` number, since 13 + 36 + 81 + 536 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 133681536.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 162021 + ... + 162843.

It is an arithmetic number, because the mean of its divisors is an integer number (3151800).

Almost surely, 2^133681536 is an apocalyptic number.

133681536 is a gapful number since it is divisible by the number (16) 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 133681536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (201715200).

133681536 is an abundant number, since it is smaller than the sum of its proper divisors (269748864).

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

133681536 is an equidigital number, since it uses as much as digits as its factorization.

133681536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893 (or 875 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 133681536 is about 11562.0731705002. The cubic root of 133681536 is about 511.3172866726.

The spelling of 133681536 in words is "one hundred thirty-three million, six hundred eighty-one thousand, five hundred thirty-six".