2399921 has 2 divisors, whose sum is σ = 2399922.
Its totient is φ = 2399920.
The previous prime is 2399911. The next prime is 2399933. The reversal of 2399921 is 1299932.
2399921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 1852321 + 547600 = 1361^2 + 740^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-2399921 is a prime.
It is a Sophie Germain prime.
It is a Chen prime.
It is a Curzon number.
It is not a weakly prime, because it can be changed into another prime (2399911) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1199960 + 1199961.
It is an arithmetic number, because the mean of its divisors is an integer number (1199961).
22399921 is an apocalyptic number.
It is an amenable number.
2399921 is a deficient number, since it is larger than the sum of its proper divisors (1).
2399921 is an equidigital number, since it uses as much as digits as its factorization.
2399921 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 8748, while the sum is 35.
The square root of 2399921 is about 1549.1678411328.
The cubic root of 2399921 is about 133.8851209669.
The spelling of 2399921 in words is "two million, three hundred ninety-nine thousand, nine hundred twenty-one".