135981840 has 80 divisors (see below), whose sum is σ = 423472896. Its totient is φ = 36096000.

The previous prime is 135981823. The next prime is 135981851. The reversal of 135981840 is 48189531.

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

It is a congruent number.

It is an unprimeable number.

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, 56665 + ... + 59015.

Almost surely, 2^135981840 is an apocalyptic number.

135981840 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 135981840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (211736448).

135981840 is an abundant number, since it is smaller than the sum of its proper divisors (287491056).

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

135981840 is a wasteful number, since it uses less digits than its factorization.

135981840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2608 (or 2602 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 135981840 is about 11661.1251601207. The cubic root of 135981840 is about 514.2334276649.

The spelling of 135981840 in words is "one hundred thirty-five million, nine hundred eighty-one thousand, eight hundred forty".