5645721 has 4 divisors (see below), whose sum is σ = 7527632. Its totient is φ = 3763812.

The previous prime is 5645713. The next prime is 5645723. The reversal of 5645721 is 1275465.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 5645721 - 2³ = 5645713 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5645723) 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 in 3 ways as a sum of consecutive naturals, for example, 940951 + ... + 940956.

It is an arithmetic number, because the mean of its divisors is an integer number (1881908).

Almost surely, 2^5645721 is an apocalyptic number.

It is an amenable number.

5645721 is a deficient number, since it is larger than the sum of its proper divisors (1881911).

5645721 is a wasteful number, since it uses less digits than its factorization.

5645721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881910.

The product of its digits is 8400, while the sum is 30.

The square root of 5645721 is about 2376.0725999009. The cubic root of 5645721 is about 178.0627750643.

The spelling of 5645721 in words is "five million, six hundred forty-five thousand, seven hundred twenty-one".