2018781 has 6 divisors (see below), whose sum is σ = 2916030. Its totient is φ = 1345848.

The previous prime is 2018773. The next prime is 2018827. The reversal of 2018781 is 1878102.

It can be written as a sum of positive squares in only one way, i.e., 1602756 + 416025 = 1266^2 + 645^2 .

It is not a de Polignac number, because 2018781 - 2³ = 2018773 is a prime.

It is a super-2 number, since 2×2018781² = 8150953451922, which contains 22 as substring.

It is an Ulam number.

It is a Curzon number.

2018781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2018741) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 112146 + ... + 112163.

It is an arithmetic number, because the mean of its divisors is an integer number (486005).

2^2018781 is an apocalyptic number.

It is an amenable number.

2018781 is a deficient number, since it is larger than the sum of its proper divisors (897249).

2018781 is a wasteful number, since it uses less digits than its factorization.

2018781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224315 (or 224312 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 2018781 is about 1420.8381329342. The cubic root of 2018781 is about 126.3852532134.

The spelling of 2018781 in words is "two million, eighteen thousand, seven hundred eighty-one".