2055721 has 4 divisors (see below), whose sum is σ = 2077012. Its totient is φ = 2034432.

The previous prime is 2055719. The next prime is 2055727. The reversal of 2055721 is 1275502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1275502 = 2 ⋅637751.

It can be written as a sum of positive squares in 2 ways, for example, as 404496 + 1651225 = 636^2 + 1285^2 .

It is a cyclic number.

It is not a de Polignac number, because 2055721 - 2¹ = 2055719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2055692 and 2055701.

It is not an unprimeable number, because it can be changed into a prime (2055727) 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, 10500 + ... + 10693.

It is an arithmetic number, because the mean of its divisors is an integer number (519253).

2^2055721 is an apocalyptic number.

It is an amenable number.

2055721 is a deficient number, since it is larger than the sum of its proper divisors (21291).

2055721 is an equidigital number, since it uses as much as digits as its factorization.

2055721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21290.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 2055721 is about 1433.7785742575. The cubic root of 2055721 is about 127.1514715729.

The spelling of 2055721 in words is "two million, fifty-five thousand, seven hundred twenty-one".