2521021 has 2 divisors, whose sum is σ = 2521022. Its totient is φ = 2521020.

The previous prime is 2521019. The next prime is 2521031. The reversal of 2521021 is 1201252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2515396 + 5625 = 1586^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 2521021 - 2¹ = 2521019 is a prime.

Together with 2521019, it forms a pair of twin primes.

It is a Chen prime.

2521021 is a lucky number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 2520992 and 2521010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2521031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1260510 + 1260511.

It is an arithmetic number, because the mean of its divisors is an integer number (1260511).

2^2521021 is an apocalyptic number.

It is an amenable number.

2521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2521021 is an equidigital number, since it uses as much as digits as its factorization.

2521021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 2521021 is about 1587.7723388446. The cubic root of 2521021 is about 136.1002180864.

Adding to 2521021 its reverse (1201252), we get a palindrome (3722273).

It can be divided in two parts, 25 and 21021, that multiplied together give a palindrome (525525).

The spelling of 2521021 in words is "two million, five hundred twenty-one thousand, twenty-one".