5640721 has 2 divisors, whose sum is σ = 5640722. Its totient is φ = 5640720.

The previous prime is 5640709. The next prime is 5640743. The reversal of 5640721 is 1270465.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4260096 + 1380625 = 2064^2 + 1175^2 .

It is a cyclic number.

It is not a de Polignac number, because 5640721 - 2⁵ = 5640689 is a prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (5640781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2820360 + 2820361.

It is an arithmetic number, because the mean of its divisors is an integer number (2820361).

Almost surely, 2^5640721 is an apocalyptic number.

It is an amenable number.

5640721 is a deficient number, since it is larger than the sum of its proper divisors (1).

5640721 is an equidigital number, since it uses as much as digits as its factorization.

5640721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 5640721 is about 2375.0202104403. The cubic root of 5640721 is about 178.0101938361.

The spelling of 5640721 in words is "five million, six hundred forty thousand, seven hundred twenty-one".