39238721 has 2 divisors, whose sum is σ = 39238722. Its totient is φ = 39238720.

The previous prime is 39238699. The next prime is 39238723. The reversal of 39238721 is 12783293.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38925121 + 313600 = 6239^2 + 560^2 .

It is an emirp because it is prime and its reverse (12783293) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39238721 is a prime.

Together with 39238723, 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 (39238723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19619360 + 19619361.

It is an arithmetic number, because the mean of its divisors is an integer number (19619361).

Almost surely, 2^39238721 is an apocalyptic number.

It is an amenable number.

39238721 is a deficient number, since it is larger than the sum of its proper divisors (1).

39238721 is an equidigital number, since it uses as much as digits as its factorization.

39238721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 35.

The square root of 39238721 is about 6264.0818161962. The cubic root of 39238721 is about 339.8116632830.

The spelling of 39238721 in words is "thirty-nine million, two hundred thirty-eight thousand, seven hundred twenty-one".