5721665 has 4 divisors (see below), whose sum is σ = 6866004. Its totient is φ = 4577328.

The previous prime is 5721659. The next prime is 5721689. The reversal of 5721665 is 5661275.

It is a happy number.

It is a Cunningham number, because it is equal to 2392²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2062096 + 3659569 = 1436^2 + 1913^2 .

It is a cyclic number.

It is not a de Polignac number, because 5721665 - 2⁴ = 5721649 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 572162 + ... + 572171.

It is an arithmetic number, because the mean of its divisors is an integer number (1716501).

Almost surely, 2^5721665 is an apocalyptic number.

It is an amenable number.

5721665 is a deficient number, since it is larger than the sum of its proper divisors (1144339).

5721665 is a wasteful number, since it uses less digits than its factorization.

5721665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1144338.

The product of its digits is 12600, while the sum is 32.

The square root of 5721665 is about 2392.0002090301. Note that the first 3 decimals coincide. The cubic root of 5721665 is about 178.8576315612.

The spelling of 5721665 in words is "five million, seven hundred twenty-one thousand, six hundred sixty-five".