135999920 has 80 divisors (see below), whose sum is σ = 377118720. Its totient is φ = 44596992.

The previous prime is 135999887. The next prime is 135999923. The reversal of 135999920 is 29999531.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (135999923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7601 + ... + 18159.

It is an arithmetic number, because the mean of its divisors is an integer number (4713984).

Almost surely, 2^135999920 is an apocalyptic number.

135999920 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 135999920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188559360).

135999920 is an abundant number, since it is smaller than the sum of its proper divisors (241118800).

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

135999920 is a wasteful number, since it uses less digits than its factorization.

135999920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10602 (or 10596 counting only the distinct ones).

The product of its (nonzero) digits is 196830, while the sum is 47.

The square root of 135999920 is about 11661.9003597184. The cubic root of 135999920 is about 514.2562172971.

The spelling of 135999920 in words is "one hundred thirty-five million, nine hundred ninety-nine thousand, nine hundred twenty".