2121110021 has 4 divisors (see below), whose sum is σ = 2121241632. Its totient is φ = 2120978412.

The previous prime is 2121109999. The next prime is 2121110027. The reversal of 2121110021 is 1200111212.

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 2121110021 - 2⁶ = 2121109957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121109984 and 2121110011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121110027) 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, 37601 + ... + 75206.

It is an arithmetic number, because the mean of its divisors is an integer number (530310408).

Almost surely, 2^2121110021 is an apocalyptic number.

It is an amenable number.

2121110021 is a deficient number, since it is larger than the sum of its proper divisors (131611).

2121110021 is a wasteful number, since it uses less digits than its factorization.

2121110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131610.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 2121110021 is about 46055.5102132199. The cubic root of 2121110021 is about 1284.8558274158.

Adding to 2121110021 its reverse (1200111212), we get a palindrome (3321221233).

The spelling of 2121110021 in words is "two billion, one hundred twenty-one million, one hundred ten thousand, twenty-one".