65721 has 8 divisors (see below), whose sum is σ = 92320. Its totient is φ = 41472.

The previous prime is 65719. The next prime is 65729. The reversal of 65721 is 12756.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65721 - 2¹ = 65719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520 + ... + 633.

It is an arithmetic number, because the mean of its divisors is an integer number (11540).

2⁶⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

65721 is a deficient number, since it is larger than the sum of its proper divisors (26599).

65721 is a wasteful number, since it uses less digits than its factorization.

65721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1175.

The product of its digits is 420, while the sum is 21.

The square root of 65721 is about 256.3610734882. The cubic root of 65721 is about 40.3553750312.

The spelling of 65721 in words is "sixty-five thousand, seven hundred twenty-one".