2121878 has 16 divisors (see below), whose sum is σ = 3554496. Its totient is φ = 941640.

The previous prime is 2121877. The next prime is 2121881. The reversal of 2121878 is 8781212.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 2121878.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121877) 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 7 ways as a sum of consecutive naturals, for example, 176 + ... + 2067.

It is an arithmetic number, because the mean of its divisors is an integer number (222156).

2^2121878 is an apocalyptic number.

2121878 is a deficient number, since it is larger than the sum of its proper divisors (1432618).

2121878 is a wasteful number, since it uses less digits than its factorization.

2121878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2299.

The product of its digits is 1792, while the sum is 29.

The square root of 2121878 is about 1456.6667429443. Note that the first 3 decimals coincide. The cubic root of 2121878 is about 128.5010875672.

The spelling of 2121878 in words is "two million, one hundred twenty-one thousand, eight hundred seventy-eight".