39393721 has 4 divisors (see below), whose sum is σ = 39742452. Its totient is φ = 39044992.

The previous prime is 39393713. The next prime is 39393727. The reversal of 39393721 is 12739393.

39393721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 193600 + 39200121 = 440^2 + 6261^2 .

It is a cyclic number.

It is not a de Polignac number, because 39393721 - 2³ = 39393713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39393727) 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 in 3 ways as a sum of consecutive naturals, for example, 174196 + ... + 174421.

It is an arithmetic number, because the mean of its divisors is an integer number (9935613).

Almost surely, 2^39393721 is an apocalyptic number.

It is an amenable number.

39393721 is a deficient number, since it is larger than the sum of its proper divisors (348731).

39393721 is a wasteful number, since it uses less digits than its factorization.

39393721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348730.

The product of its digits is 30618, while the sum is 37.

The square root of 39393721 is about 6276.4417467224. The cubic root of 39393721 is about 340.2585144648.

The spelling of 39393721 in words is "thirty-nine million, three hundred ninety-three thousand, seven hundred twenty-one".