47187721 has 4 divisors (see below), whose sum is σ = 53928832. Its totient is φ = 40446612.

The previous prime is 47187689. The next prime is 47187731. The reversal of 47187721 is 12778174.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12778174 = 2 ⋅6389087.

It is a cyclic number.

It is not a de Polignac number, because 47187721 - 2⁵ = 47187689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (47187731) 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, 3370545 + ... + 3370558.

It is an arithmetic number, because the mean of its divisors is an integer number (13482208).

Almost surely, 2^47187721 is an apocalyptic number.

It is an amenable number.

47187721 is a deficient number, since it is larger than the sum of its proper divisors (6741111).

47187721 is an equidigital number, since it uses as much as digits as its factorization.

47187721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6741110.

The product of its digits is 21952, while the sum is 37.

The square root of 47187721 is about 6869.3319180252. The cubic root of 47187721 is about 361.3624324870.

The spelling of 47187721 in words is "forty-seven million, one hundred eighty-seven thousand, seven hundred twenty-one".