2130021 has 12 divisors (see below), whose sum is σ = 3183180. Its totient is φ = 1370880.

The previous prime is 2130013. The next prime is 2130031. The reversal of 2130021 is 1200312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 950625 + 1179396 = 975^2 + 1086^2 .

It is not a de Polignac number, because 2130021 - 2³ = 2130013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2129985 and 2130012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2130001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3820 + ... + 4341.

It is an arithmetic number, because the mean of its divisors is an integer number (265265).

2^2130021 is an apocalyptic number.

It is an amenable number.

2130021 is a deficient number, since it is larger than the sum of its proper divisors (1053159).

2130021 is a wasteful number, since it uses less digits than its factorization.

2130021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8196 (or 8193 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 2130021 is about 1459.4591463964. The cubic root of 2130021 is about 128.6652579632.

Adding to 2130021 its reverse (1200312), we get a palindrome (3330333).

It can be divided in two parts, 21300 and 21, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 2130021 in words is "two million, one hundred thirty thousand, twenty-one".