2121786 has 12 divisors (see below), whose sum is σ = 4597242. Its totient is φ = 707256.

The previous prime is 2121781. The next prime is 2121793. The reversal of 2121786 is 6871212.

It can be written as a sum of positive squares in only one way, i.e., 2117025 + 4761 = 1455^2 + 69^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2121781) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 58921 + ... + 58956.

2^2121786 is an apocalyptic number.

2121786 is an abundant number, since it is smaller than the sum of its proper divisors (2475456).

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

2121786 is a wasteful number, since it uses less digits than its factorization.

2121786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117885 (or 117882 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 2121786 is about 1456.6351636563. The cubic root of 2121786 is about 128.4992303648.

Adding to 2121786 its reverse (6871212), we get a palindrome (8992998).

The spelling of 2121786 in words is "two million, one hundred twenty-one thousand, seven hundred eighty-six".