135699840 has 128 divisors (see below), whose sum is σ = 480664800. Its totient is φ = 36182016.

The previous prime is 135699829. The next prime is 135699841. The reversal of 135699840 is 48996531.

It is a happy number.

135699840 is a `hidden beast` number, since 1 + 3 + 569 + 9 + 84 + 0 = 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 (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135699841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13354 + ... + 21206.

Almost surely, 2^135699840 is an apocalyptic number.

135699840 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 135699840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (240332400).

135699840 is an abundant number, since it is smaller than the sum of its proper divisors (344964960).

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

135699840 is an equidigital number, since it uses as much as digits as its factorization.

135699840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7881 (or 7863 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 135699840 is about 11649.0274272147. The cubic root of 135699840 is about 513.8777081419.

It can be divided in two parts, 13569 and 9840, that added together give a square (23409 = 153²).

The spelling of 135699840 in words is "one hundred thirty-five million, six hundred ninety-nine thousand, eight hundred forty".