155720 has 32 divisors (see below), whose sum is σ = 372600. Its totient is φ = 58368.

The previous prime is 155719. The next prime is 155723. The reversal of 155720 is 27551.

It can be written as a sum of positive squares in 4 ways, for example, as 155236 + 484 = 394^2 + 22^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 155692 and 155701.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 155720.

It is not an unprimeable number, because it can be changed into a prime (155723) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 566 + ... + 794.

2¹⁵⁵⁷²⁰ is an apocalyptic number.

155720 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 155720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186300).

155720 is an abundant number, since it is smaller than the sum of its proper divisors (216880).

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

155720 is a wasteful number, since it uses less digits than its factorization.

155720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 155720 is about 394.6137351892. The cubic root of 155720 is about 53.7998995774.

The spelling of 155720 in words is "one hundred fifty-five thousand, seven hundred twenty".