2305721 has 8 divisors (see below), whose sum is σ = 2528064. Its totient is φ = 2085520.

The previous prime is 2305711. The next prime is 2305733. The reversal of 2305721 is 1275032.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2305721 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2305693 and 2305702.

It is not an unprimeable number, because it can be changed into a prime (2305711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2495 + ... + 3291.

It is an arithmetic number, because the mean of its divisors is an integer number (316008).

2^2305721 is an apocalyptic number.

It is an amenable number.

2305721 is a deficient number, since it is larger than the sum of its proper divisors (222343).

2305721 is a wasteful number, since it uses less digits than its factorization.

2305721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1071.

The product of its (nonzero) digits is 420, while the sum is 20.

The square root of 2305721 is about 1518.4600752078. The cubic root of 2305721 is about 132.1099672850.

The spelling of 2305721 in words is "two million, three hundred five thousand, seven hundred twenty-one".