47171721 has 4 divisors (see below), whose sum is σ = 62895632. Its totient is φ = 31447812.

The previous prime is 47171717. The next prime is 47171723. The reversal of 47171721 is 12717174.

47171721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 47171721 - 2² = 47171717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (47171723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7861951 + ... + 7861956.

It is an arithmetic number, because the mean of its divisors is an integer number (15723908).

Almost surely, 2^47171721 is an apocalyptic number.

It is an amenable number.

47171721 is a deficient number, since it is larger than the sum of its proper divisors (15723911).

47171721 is a wasteful number, since it uses less digits than its factorization.

47171721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15723910.

The product of its digits is 2744, while the sum is 30.

The square root of 47171721 is about 6868.1672227749. The cubic root of 47171721 is about 361.3215853316.

Adding to 47171721 its reverse (12717174), we get a palindrome (59888895).

The spelling of 47171721 in words is "forty-seven million, one hundred seventy-one thousand, seven hundred twenty-one".