201780 has 72 divisors (see below), whose sum is σ = 655200. Its totient is φ = 50112.

The previous prime is 201769. The next prime is 201781. The reversal of 201780 is 87102.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201781) by changing a digit.

201780 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 (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3391 + ... + 3449.

It is an arithmetic number, because the mean of its divisors is an integer number (9100).

2²⁰¹⁷⁸⁰ is an apocalyptic number.

201780 is a gapful number since it is divisible by the number (20) 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 201780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327600).

201780 is an abundant number, since it is smaller than the sum of its proper divisors (453420).

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

201780 is a wasteful number, since it uses less digits than its factorization.

201780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 201780 is about 449.1992876219. The cubic root of 201780 is about 58.6533343212.

Adding to 201780 its reverse (87102), we get a palindrome (288882).

The spelling of 201780 in words is "two hundred one thousand, seven hundred eighty".