2520021 has 32 divisors (see below), whose sum is σ = 4096000. Its totient is φ = 1375920.

The previous prime is 2520017. The next prime is 2520031. The reversal of 2520021 is 1200252.

It is not a de Polignac number, because 2520021 - 2² = 2520017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2519979 and 2520006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2520031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31860 + ... + 31938.

It is an arithmetic number, because the mean of its divisors is an integer number (128000).

2^2520021 is an apocalyptic number.

2520021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2520021 is a deficient number, since it is larger than the sum of its proper divisors (1575979).

2520021 is an equidigital number, since it uses as much as digits as its factorization.

2520021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 2520021 is about 1587.4574010033. The cubic root of 2520021 is about 136.0822203231.

Adding to 2520021 its reverse (1200252), we get a palindrome (3720273).

The spelling of 2520021 in words is "two million, five hundred twenty thousand, twenty-one".