7720639 has 2 divisors, whose sum is σ = 7720640. Its totient is φ = 7720638.

The previous prime is 7720637. The next prime is 7720649. The reversal of 7720639 is 9360277.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 7720639 - 2¹ = 7720637 is a prime.

Together with 7720637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7720633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3860319 + 3860320.

It is an arithmetic number, because the mean of its divisors is an integer number (3860320).

Almost surely, 2^7720639 is an apocalyptic number.

7720639 is a deficient number, since it is larger than the sum of its proper divisors (1).

7720639 is an equidigital number, since it uses as much as digits as its factorization.

7720639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15876, while the sum is 34.

The square root of 7720639 is about 2778.6037860767. The cubic root of 7720639 is about 197.6443552867.

The spelling of 7720639 in words is "seven million, seven hundred twenty thousand, six hundred thirty-nine".