7720649 has 2 divisors, whose sum is σ = 7720650. Its totient is φ = 7720648.

The previous prime is 7720639. The next prime is 7720667. The reversal of 7720649 is 9460277.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5031049 + 2689600 = 2243^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 7720649 - 2⁴ = 7720633 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (7720619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3860324 + 3860325.

It is an arithmetic number, because the mean of its divisors is an integer number (3860325).

Almost surely, 2^7720649 is an apocalyptic number.

It is an amenable number.

7720649 is a deficient number, since it is larger than the sum of its proper divisors (1).

7720649 is an equidigital number, since it uses as much as digits as its factorization.

7720649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 35.

The square root of 7720649 is about 2778.6055855411. The cubic root of 7720649 is about 197.6444406183.

The spelling of 7720649 in words is "seven million, seven hundred twenty thousand, six hundred forty-nine".