2908721 has 2 divisors, whose sum is σ = 2908722. Its totient is φ = 2908720.

The previous prime is 2908687. The next prime is 2908723. The reversal of 2908721 is 1278092.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1597696 + 1311025 = 1264^2 + 1145^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2908721 is a prime.

Together with 2908723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2908723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1454360 + 1454361.

It is an arithmetic number, because the mean of its divisors is an integer number (1454361).

2^2908721 is an apocalyptic number.

It is an amenable number.

2908721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2908721 is an equidigital number, since it uses as much as digits as its factorization.

2908721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 2908721 is about 1705.4972881831. The cubic root of 2908721 is about 142.7471201916.

The spelling of 2908721 in words is "two million, nine hundred eight thousand, seven hundred twenty-one".