39538721 has 2 divisors, whose sum is σ = 39538722. Its totient is φ = 39538720.

The previous prime is 39538711. The next prime is 39538739. The reversal of 39538721 is 12783593.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23658496 + 15880225 = 4864^2 + 3985^2 .

It is an emirp because it is prime and its reverse (12783593) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 39538721 - 2¹⁰ = 39537697 is a prime.

It is not a weakly prime, because it can be changed into another prime (39538711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19769360 + 19769361.

It is an arithmetic number, because the mean of its divisors is an integer number (19769361).

Almost surely, 2^39538721 is an apocalyptic number.

It is an amenable number.

39538721 is a deficient number, since it is larger than the sum of its proper divisors (1).

39538721 is an equidigital number, since it uses as much as digits as its factorization.

39538721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 38.

The square root of 39538721 is about 6287.9822677867. The cubic root of 39538721 is about 340.6754766371.

The spelling of 39538721 in words is "thirty-nine million, five hundred thirty-eight thousand, seven hundred twenty-one".