133840 has 40 divisors (see below), whose sum is σ = 357120. Its totient is φ = 45696.

The previous prime is 133831. The next prime is 133843. The reversal of 133840 is 48331.

It is a tau number, because it is divible by the number of its divisors (40).

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133843) by changing a digit.

133840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 441 + ... + 679.

It is an arithmetic number, because the mean of its divisors is an integer number (8928).

2¹³³⁸⁴⁰ is an apocalyptic number.

133840 is a gapful number since it is divisible by the number (10) 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 133840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178560).

133840 is an abundant number, since it is smaller than the sum of its proper divisors (223280).

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

133840 is a wasteful number, since it uses less digits than its factorization.

133840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 133840 is about 365.8414957328. The cubic root of 133840 is about 51.1519242731.

It can be divided in two parts, 1338 and 40, that added together give a triangular number (1378 = T₅₂).

The spelling of 133840 in words is "one hundred thirty-three thousand, eight hundred forty".