5665921 has 4 divisors (see below), whose sum is σ = 5819092. Its totient is φ = 5512752.

The previous prime is 5665903. The next prime is 5665937. The reversal of 5665921 is 1295665.

It is a happy number.

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 5125696 + 540225 = 2264^2 + 735^2 .

It is a cyclic number.

It is not a de Polignac number, because 5665921 - 2¹⁵ = 5633153 is a prime.

It is a Duffinian number.

5665921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (5635921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76530 + ... + 76603.

It is an arithmetic number, because the mean of its divisors is an integer number (1454773).

Almost surely, 2^5665921 is an apocalyptic number.

It is an amenable number.

5665921 is a deficient number, since it is larger than the sum of its proper divisors (153171).

5665921 is a wasteful number, since it uses less digits than its factorization.

5665921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153170.

The product of its digits is 16200, while the sum is 34.

The square root of 5665921 is about 2380.3195163675. The cubic root of 5665921 is about 178.2748877293.

The spelling of 5665921 in words is "five million, six hundred sixty-five thousand, nine hundred twenty-one".