2101780 has 24 divisors (see below), whose sum is σ = 4646880. Its totient is φ = 796320.

The previous prime is 2101751. The next prime is 2101789. The reversal of 2101780 is 871012.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101789) 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, 2386 + ... + 3145.

It is an arithmetic number, because the mean of its divisors is an integer number (193620).

2^2101780 is an apocalyptic number.

2101780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2101780 is an abundant number, since it is smaller than the sum of its proper divisors (2545100).

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

2101780 is a wasteful number, since it uses less digits than its factorization.

2101780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5559 (or 5557 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 2101780 is about 1449.7517028788. The cubic root of 2101780 is about 128.0940877239.

Adding to 2101780 its reverse (871012), we get a palindrome (2972792).

The spelling of 2101780 in words is "two million, one hundred one thousand, seven hundred eighty".