39720643 has 2 divisors, whose sum is σ = 39720644. Its totient is φ = 39720642.

The previous prime is 39720623. The next prime is 39720679. The reversal of 39720643 is 34602793.

39720643 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 is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39720643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 39720599 and 39720608.

It is not a weakly prime, because it can be changed into another prime (39720613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19860321 + 19860322.

It is an arithmetic number, because the mean of its divisors is an integer number (19860322).

Almost surely, 2^39720643 is an apocalyptic number.

39720643 is a deficient number, since it is larger than the sum of its proper divisors (1).

39720643 is an equidigital number, since it uses as much as digits as its factorization.

39720643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 34.

The square root of 39720643 is about 6302.4315148996. The cubic root of 39720643 is about 341.1971724277.

The spelling of 39720643 in words is "thirty-nine million, seven hundred twenty thousand, six hundred forty-three".