63721 has 4 divisors (see below), whose sum is σ = 72832. Its totient is φ = 54612.

The previous prime is 63719. The next prime is 63727. The reversal of 63721 is 12736.

63721 is nontrivially palindromic in base 3 and base 15.

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 63721 - 2¹ = 63719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63727) 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, 4545 + ... + 4558.

It is an arithmetic number, because the mean of its divisors is an integer number (18208).

2⁶³⁷²¹ is an apocalyptic number.

It is an amenable number.

63721 is a deficient number, since it is larger than the sum of its proper divisors (9111).

63721 is an equidigital number, since it uses as much as digits as its factorization.

63721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9110.

The product of its digits is 252, while the sum is 19.

The square root of 63721 is about 252.4301883690. The cubic root of 63721 is about 39.9417903320.

It can be divided in two parts, 63 and 721, that added together give a square (784 = 28²).

The spelling of 63721 in words is "sixty-three thousand, seven hundred twenty-one".