2390021 has 2 divisors, whose sum is σ = 2390022. Its totient is φ = 2390020.

The previous prime is 2390009. The next prime is 2390023. The reversal of 2390021 is 1200932.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1999396 + 390625 = 1414^2 + 625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2390021 is a prime.

Together with 2390023, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2390023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1195010 + 1195011.

It is an arithmetic number, because the mean of its divisors is an integer number (1195011).

2^2390021 is an apocalyptic number.

It is an amenable number.

2390021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2390021 is an equidigital number, since it uses as much as digits as its factorization.

2390021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 2390021 is about 1545.9692752445. The cubic root of 2390021 is about 133.7007691407.

Adding to 2390021 its reverse (1200932), we get a palindrome (3590953).

The spelling of 2390021 in words is "two million, three hundred ninety thousand, twenty-one".