65639 has 4 divisors (see below), whose sum is σ = 75024. Its totient is φ = 56256.

The previous prime is 65633. The next prime is 65647. The reversal of 65639 is 93656.

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

It is a cyclic number.

It is not a de Polignac number, because 65639 - 2¹² = 61543 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65633) 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, 4682 + ... + 4695.

It is an arithmetic number, because the mean of its divisors is an integer number (18756).

2⁶⁵⁶³⁹ is an apocalyptic number.

65639 is a deficient number, since it is larger than the sum of its proper divisors (9385).

65639 is an equidigital number, since it uses as much as digits as its factorization.

65639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9384.

The product of its digits is 4860, while the sum is 29.

The square root of 65639 is about 256.2010928938. The cubic root of 65639 is about 40.3385842643.

The spelling of 65639 in words is "sixty-five thousand, six hundred thirty-nine".