2563721 has 4 divisors (see below), whose sum is σ = 2567700. Its totient is φ = 2559744.

The previous prime is 2563711. The next prime is 2563723. The reversal of 2563721 is 1273652.

2563721 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.

It can be written as a sum of positive squares in 2 ways, for example, as 2190400 + 373321 = 1480^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 2563721 - 2⁶ = 2563657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2563723) 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 3 ways as a sum of consecutive naturals, for example, 776 + ... + 2393.

It is an arithmetic number, because the mean of its divisors is an integer number (641925).

2^2563721 is an apocalyptic number.

It is an amenable number.

2563721 is a deficient number, since it is larger than the sum of its proper divisors (3979).

2563721 is an equidigital number, since it uses as much as digits as its factorization.

2563721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3978.

The product of its digits is 2520, while the sum is 26.

The square root of 2563721 is about 1601.1623902653. The cubic root of 2563721 is about 136.8643230275.

It can be divided in two parts, 256 and 3721, that multiplied together give a square (952576 = 976²).

The spelling of 2563721 in words is "two million, five hundred sixty-three thousand, seven hundred twenty-one".