47721 has 4 divisors (see below), whose sum is σ = 63632. Its totient is φ = 31812.

The previous prime is 47717. The next prime is 47737. The reversal of 47721 is 12774.

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 47721 - 2² = 47717 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (47701) 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, 7951 + ... + 7956.

It is an arithmetic number, because the mean of its divisors is an integer number (15908).

2⁴⁷⁷²¹ is an apocalyptic number.

It is an amenable number.

47721 is a deficient number, since it is larger than the sum of its proper divisors (15911).

47721 is a wasteful number, since it uses less digits than its factorization.

47721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15910.

The product of its digits is 392, while the sum is 21.

The square root of 47721 is about 218.4513675856. The cubic root of 47721 is about 36.2718615654.

The spelling of 47721 in words is "forty-seven thousand, seven hundred twenty-one", and thus it is an iban number.