2121813 has 12 divisors (see below), whose sum is σ = 3077568. Its totient is φ = 1408680.

The previous prime is 2121809. The next prime is 2121829. The reversal of 2121813 is 3181212.

It is not a de Polignac number, because 2121813 - 2² = 2121809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121803) 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 11 ways as a sum of consecutive naturals, for example, 3606 + ... + 4152.

It is an arithmetic number, because the mean of its divisors is an integer number (256464).

2^2121813 is an apocalyptic number.

It is an amenable number.

2121813 is a deficient number, since it is larger than the sum of its proper divisors (955755).

2121813 is a wasteful number, since it uses less digits than its factorization.

2121813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984 (or 981 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 2121813 is about 1456.6444315618. The cubic root of 2121813 is about 128.4997754189.

It can be divided in two parts, 212 and 1813, that added together give a square (2025 = 45²).

The spelling of 2121813 in words is "two million, one hundred twenty-one thousand, eight hundred thirteen".