133639920 has 120 divisors (see below), whose sum is σ = 472477200. Its totient is φ = 33758208.

The previous prime is 133639861. The next prime is 133639921. The reversal of 133639920 is 29936331.

It is a happy number.

133639920 is a `hidden beast` number, since 13 + 3 + 639 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133639921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8796 + ... + 18564.

It is an arithmetic number, because the mean of its divisors is an integer number (3937310).

Almost surely, 2^133639920 is an apocalyptic number.

133639920 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 133639920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (236238600).

133639920 is an abundant number, since it is smaller than the sum of its proper divisors (338837280).

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

133639920 is a wasteful number, since it uses less digits than its factorization.

133639920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9807 (or 9798 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 36.

The square root of 133639920 is about 11560.2733531695. The cubic root of 133639920 is about 511.2642222796.

The spelling of 133639920 in words is "one hundred thirty-three million, six hundred thirty-nine thousand, nine hundred twenty".