2121755 has 4 divisors (see below), whose sum is σ = 2546112. Its totient is φ = 1697400.

The previous prime is 2121751. The next prime is 2121761. The reversal of 2121755 is 5571212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 2121755 - 2² = 2121751 is a prime.

It is a super-3 number, since 3×2121755³ = 28655431831093331625, which contains 333 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121755.

It is not an unprimeable number, because it can be changed into a prime (2121751) 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 3 ways as a sum of consecutive naturals, for example, 212171 + ... + 212180.

It is an arithmetic number, because the mean of its divisors is an integer number (636528).

2^2121755 is an apocalyptic number.

2121755 is a deficient number, since it is larger than the sum of its proper divisors (424357).

2121755 is an equidigital number, since it uses as much as digits as its factorization.

2121755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424356.

The product of its digits is 700, while the sum is 23.

The square root of 2121755 is about 1456.6245226550. The cubic root of 2121755 is about 128.4986045562.

Adding to 2121755 its reverse (5571212), we get a palindrome (7692967).

The spelling of 2121755 in words is "two million, one hundred twenty-one thousand, seven hundred fifty-five".