2121890 has 16 divisors (see below), whose sum is σ = 3877632. Its totient is φ = 835824.

The previous prime is 2121881. The next prime is 2121893. The reversal of 2121890 is 981212.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2121893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 914 + ... + 2253.

It is an arithmetic number, because the mean of its divisors is an integer number (242352).

2^2121890 is an apocalyptic number.

2121890 is a deficient number, since it is larger than the sum of its proper divisors (1755742).

2121890 is a wasteful number, since it uses less digits than its factorization.

2121890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3241.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 2121890 is about 1456.6708619314. The cubic root of 2121890 is about 128.5013298070.

The spelling of 2121890 in words is "two million, one hundred twenty-one thousand, eight hundred ninety".