65579721 has 4 divisors (see below), whose sum is σ = 87439632. Its totient is φ = 43719812.

The previous prime is 65579719. The next prime is 65579729. The reversal of 65579721 is 12797556.

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 a cyclic number.

It is not a de Polignac number, because 65579721 - 2¹ = 65579719 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65579729) 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, 10929951 + ... + 10929956.

It is an arithmetic number, because the mean of its divisors is an integer number (21859908).

Almost surely, 2^65579721 is an apocalyptic number.

It is an amenable number.

65579721 is a deficient number, since it is larger than the sum of its proper divisors (21859911).

65579721 is a wasteful number, since it uses less digits than its factorization.

65579721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21859910.

The product of its digits is 132300, while the sum is 42.

The square root of 65579721 is about 8098.1307102318. The cubic root of 65579721 is about 403.2643726251.

The spelling of 65579721 in words is "sixty-five million, five hundred seventy-nine thousand, seven hundred twenty-one".