2440021 has 2 divisors, whose sum is σ = 2440022. Its totient is φ = 2440020.

The previous prime is 2440019. The next prime is 2440043. The reversal of 2440021 is 1200442.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1240996 + 1199025 = 1114^2 + 1095^2 .

It is a cyclic number.

It is not a de Polignac number, because 2440021 - 2¹ = 2440019 is a prime.

Together with 2440019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2439983 and 2440010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2440091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1220010 + 1220011.

It is an arithmetic number, because the mean of its divisors is an integer number (1220011).

2^2440021 is an apocalyptic number.

It is an amenable number.

2440021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2440021 is an equidigital number, since it uses as much as digits as its factorization.

2440021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 2440021 is about 1562.0566571031. The cubic root of 2440021 is about 134.6266961672.

Adding to 2440021 its reverse (1200442), we get a palindrome (3640463).

The spelling of 2440021 in words is "two million, four hundred forty thousand, twenty-one".