5640021 has 12 divisors (see below), whose sum is σ = 8367372. Its totient is φ = 3658176.

The previous prime is 5639989. The next prime is 5640031. The reversal of 5640021 is 1200465.

It is a happy number.

5640021 is a `hidden beast` number, since 5 + 640 + 0 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3651921 + 1988100 = 1911^2 + 1410^2 .

It is not a de Polignac number, because 5640021 - 2⁵ = 5639989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 5639976 and 5640003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5640031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8136 + ... + 8801.

It is an arithmetic number, because the mean of its divisors is an integer number (697281).

Almost surely, 2^5640021 is an apocalyptic number.

It is an amenable number.

5640021 is a deficient number, since it is larger than the sum of its proper divisors (2727351).

5640021 is a wasteful number, since it uses less digits than its factorization.

5640021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16980 (or 16977 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 5640021 is about 2374.8728387011. The cubic root of 5640021 is about 178.0028299849.

Adding to 5640021 its reverse (1200465), we get a palindrome (6840486).

The spelling of 5640021 in words is "five million, six hundred forty thousand, twenty-one".