2123205021 has 32 divisors (see below), whose sum is σ = 3806311680. Its totient is φ = 1141890048.

The previous prime is 2123205011. The next prime is 2123205031. The reversal of 2123205021 is 1205023212.

It is an interprime number because it is at equal distance from previous prime (2123205011) and next prime (2123205031).

It is not a de Polignac number, because 2123205021 - 2¹⁹ = 2122680733 is a prime.

It is a super-2 number, since 2×2123205021² = 9015999122399220882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2123204985 and 2123205003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123205011) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 327196 + ... + 333621.

It is an arithmetic number, because the mean of its divisors is an integer number (118947240).

Almost surely, 2^2123205021 is an apocalyptic number.

2123205021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2123205021 is a deficient number, since it is larger than the sum of its proper divisors (1683106659).

2123205021 is a wasteful number, since it uses less digits than its factorization.

2123205021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660850 (or 660844 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 2123205021 is about 46078.2488925089. The cubic root of 2123205021 is about 1285.2787014778.

Adding to 2123205021 its reverse (1205023212), we get a palindrome (3328228233).

The spelling of 2123205021 in words is "two billion, one hundred twenty-three million, two hundred five thousand, twenty-one".