2113123021 has 8 divisors (see below), whose sum is σ = 2205814424. Its totient is φ = 2022304320.

The previous prime is 2113123009. The next prime is 2113123027. The reversal of 2113123021 is 1203213112.

It can be written as a sum of positive squares in 4 ways, for example, as 9066121 + 2104056900 = 3011^2 + 45870^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2113123021 - 2⁵ = 2113122989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2113122986 and 2113123004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2113123027) 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, 465870 + ... + 470383.

It is an arithmetic number, because the mean of its divisors is an integer number (275726803).

Almost surely, 2^2113123021 is an apocalyptic number.

It is an amenable number.

2113123021 is a deficient number, since it is larger than the sum of its proper divisors (92691403).

2113123021 is an equidigital number, since it uses as much as digits as its factorization.

2113123021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936351.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 2113123021 is about 45968.7178524701. The cubic root of 2113123021 is about 1283.2410988002.

Adding to 2113123021 its reverse (1203213112), we get a palindrome (3316336133).

Subtracting from 2113123021 its reverse (1203213112), we obtain a palindrome (909909909).

The spelling of 2113123021 in words is "two billion, one hundred thirteen million, one hundred twenty-three thousand, twenty-one".