5665639 has 4 divisors (see below), whose sum is σ = 6475024. Its totient is φ = 4856256.

The previous prime is 5665631. The next prime is 5665661. The reversal of 5665639 is 9365665.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9365665 = 5 ⋅1873133.

It is a cyclic number.

It is not a de Polignac number, because 5665639 - 2³ = 5665631 is a prime.

It is a Duffinian number.

5665639 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5665631) 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, 404682 + ... + 404695.

It is an arithmetic number, because the mean of its divisors is an integer number (1618756).

Almost surely, 2^5665639 is an apocalyptic number.

5665639 is a deficient number, since it is larger than the sum of its proper divisors (809385).

5665639 is an equidigital number, since it uses as much as digits as its factorization.

5665639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 809384.

The product of its digits is 145800, while the sum is 40.

The square root of 5665639 is about 2380.2602798854. The cubic root of 5665639 is about 178.2719300253.

The spelling of 5665639 in words is "five million, six hundred sixty-five thousand, six hundred thirty-nine".