2783781 has 64 divisors (see below), whose sum is σ = 5591040. Its totient is φ = 1321920.

The previous prime is 2783779. The next prime is 2783789. The reversal of 2783781 is 1873872.

2783781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2783781 - 2¹ = 2783779 is a prime.

It is a super-2 number, since 2×2783781² = 15498873311922, which contains 22 as substring.

It is a Curzon number.

2783781 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2783789) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 26976 + ... + 27078.

It is an arithmetic number, because the mean of its divisors is an integer number (87360).

2^2783781 is an apocalyptic number.

2783781 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2783781 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

2783781 is a wasteful number, since it uses less digits than its factorization.

2783781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 137 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 2783781 is about 1668.4666613391. The cubic root of 2783781 is about 140.6733042946.

Subtracting from 2783781 its reverse (1873872), we obtain a palindrome (909909).

The spelling of 2783781 in words is "two million, seven hundred eighty-three thousand, seven hundred eighty-one".