2106122821 has 4 divisors (see below), whose sum is σ = 2297588544. Its totient is φ = 1914657100.

The previous prime is 2106122797. The next prime is 2106122827. The reversal of 2106122821 is 1282216012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2106122821 - 2⁹ = 2106122309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2106122827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95732845 + ... + 95732866.

It is an arithmetic number, because the mean of its divisors is an integer number (574397136).

Almost surely, 2^2106122821 is an apocalyptic number.

It is an amenable number.

2106122821 is a deficient number, since it is larger than the sum of its proper divisors (191465723).

2106122821 is a wasteful number, since it uses less digits than its factorization.

2106122821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191465722.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 2106122821 is about 45892.5137794826. The cubic root of 2106122821 is about 1281.8225219838.

Adding to 2106122821 its reverse (1282216012), we get a palindrome (3388338833).

The spelling of 2106122821 in words is "two billion, one hundred six million, one hundred twenty-two thousand, eight hundred twenty-one".