5638021 has 2 divisors, whose sum is σ = 5638022. Its totient is φ = 5638020.

The previous prime is 5638019. The next prime is 5638037. The reversal of 5638021 is 1208365.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4452100 + 1185921 = 2110^2 + 1089^2 .

It is a cyclic number.

It is not a de Polignac number, because 5638021 - 2¹ = 5638019 is a prime.

Together with 5638019, it forms a pair of twin primes.

5638021 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5638051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2819010 + 2819011.

It is an arithmetic number, because the mean of its divisors is an integer number (2819011).

Almost surely, 2^5638021 is an apocalyptic number.

It is an amenable number.

5638021 is a deficient number, since it is larger than the sum of its proper divisors (1).

5638021 is an equidigital number, since it uses as much as digits as its factorization.

5638021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 5638021 is about 2374.4517261886. The cubic root of 5638021 is about 177.9817870521.

The spelling of 5638021 in words is "five million, six hundred thirty-eight thousand, twenty-one".