2509721 has 2 divisors, whose sum is σ = 2509722. Its totient is φ = 2509720.

The previous prime is 2509687. The next prime is 2509757. The reversal of 2509721 is 1279052.

2509721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1597696 + 912025 = 1264^2 + 955^2 .

It is a cyclic number.

It is not a de Polignac number, because 2509721 - 2¹⁰ = 2508697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2509621) 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, 1254860 + 1254861.

It is an arithmetic number, because the mean of its divisors is an integer number (1254861).

2^2509721 is an apocalyptic number.

It is an amenable number.

2509721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2509721 is an equidigital number, since it uses as much as digits as its factorization.

2509721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 2509721 is about 1584.2098977093. The cubic root of 2509721 is about 135.8965656728.

The spelling of 2509721 in words is "two million, five hundred nine thousand, seven hundred twenty-one".