65995509 has 4 divisors (see below), whose sum is σ = 87994016. Its totient is φ = 43997004.

The previous prime is 65995477. The next prime is 65995519. The reversal of 65995509 is 90559956.

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 65995509 - 2⁵ = 65995477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65995519) 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, 10999249 + ... + 10999254.

It is an arithmetic number, because the mean of its divisors is an integer number (21998504).

Almost surely, 2^65995509 is an apocalyptic number.

It is an amenable number.

65995509 is a deficient number, since it is larger than the sum of its proper divisors (21998507).

65995509 is a wasteful number, since it uses less digits than its factorization.

65995509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21998506.

The product of its (nonzero) digits is 546750, while the sum is 48.

The square root of 65995509 is about 8123.7619979908. The cubic root of 65995509 is about 404.1148355872.

The spelling of 65995509 in words is "sixty-five million, nine hundred ninety-five thousand, five hundred nine".