2257721 has 2 divisors, whose sum is σ = 2257722. Its totient is φ = 2257720.

The previous prime is 2257709. The next prime is 2257733. The reversal of 2257721 is 1277522.

2257721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (2257709) and next prime (2257733).

It can be written as a sum of positive squares in only one way, i.e., 1297321 + 960400 = 1139^2 + 980^2 .

It is a cyclic number.

It is not a de Polignac number, because 2257721 - 2¹⁰ = 2256697 is a prime.

It is a super-2 number, since 2×2257721² = 10194608227682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2257771) 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 as a sum of consecutive naturals, namely, 1128860 + 1128861.

It is an arithmetic number, because the mean of its divisors is an integer number (1128861).

2^2257721 is an apocalyptic number.

It is an amenable number.

2257721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2257721 is an equidigital number, since it uses as much as digits as its factorization.

2257721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1960, while the sum is 26.

The square root of 2257721 is about 1502.5714625268. The cubic root of 2257721 is about 131.1867855829.

The spelling of 2257721 in words is "two million, two hundred fifty-seven thousand, seven hundred twenty-one".