2381721 has 8 divisors (see below), whose sum is σ = 3182784. Its totient is φ = 1584240.

The previous prime is 2381693. The next prime is 2381737. The reversal of 2381721 is 1271832.

2381721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 2381721 - 2⁵ = 2381689 is a prime.

It is a Curzon number.

2381721 is a lucky number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 2381691 and 2381700.

It is not an unprimeable number, because it can be changed into a prime (2381791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1980 + ... + 2946.

It is an arithmetic number, because the mean of its divisors is an integer number (397848).

2^2381721 is an apocalyptic number.

It is an amenable number.

2381721 is a deficient number, since it is larger than the sum of its proper divisors (801063).

2381721 is an equidigital number, since it uses as much as digits as its factorization.

2381721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1791.

The product of its digits is 672, while the sum is 24.

The square root of 2381721 is about 1543.2825405609. The cubic root of 2381721 is about 133.5458188333.

The spelling of 2381721 in words is "two million, three hundred eighty-one thousand, seven hundred twenty-one".