155840 has 28 divisors (see below), whose sum is σ = 371856. Its totient is φ = 62208.

The previous prime is 155833. The next prime is 155849. The reversal of 155840 is 48551.

155840 is nontrivially palindromic in base 3.

It is a super-2 number, since 2×155840² = 48572211200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (155849) by changing a digit.

155840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77 + ... + 563.

2¹⁵⁵⁸⁴⁰ is an apocalyptic number.

155840 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 155840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185928).

155840 is an abundant number, since it is smaller than the sum of its proper divisors (216016).

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

155840 is an equidigital number, since it uses as much as digits as its factorization.

155840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 155840 is about 394.7657533272. The cubic root of 155840 is about 53.8137156796.

The spelling of 155840 in words is "one hundred fifty-five thousand, eight hundred forty".