39668729 has 2 divisors, whose sum is σ = 39668730. Its totient is φ = 39668728.

The previous prime is 39668687. The next prime is 39668731. The reversal of 39668729 is 92786693.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 19598329 = 4480^2 + 4427^2 .

It is an emirp because it is prime and its reverse (92786693) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 39668729 - 2²⁴ = 22891513 is a prime.

Together with 39668731, 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 (39668749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19834364 + 19834365.

It is an arithmetic number, because the mean of its divisors is an integer number (19834365).

Almost surely, 2^39668729 is an apocalyptic number.

It is an amenable number.

39668729 is a deficient number, since it is larger than the sum of its proper divisors (1).

39668729 is an equidigital number, since it uses as much as digits as its factorization.

39668729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 50.

The square root of 39668729 is about 6298.3115991510. The cubic root of 39668729 is about 341.0484619078.

The spelling of 39668729 in words is "thirty-nine million, six hundred sixty-eight thousand, seven hundred twenty-nine".