38520721 has 4 divisors (see below), whose sum is σ = 38751552. Its totient is φ = 38289892.

The previous prime is 38520697. The next prime is 38520739. The reversal of 38520721 is 12702583.

38520721 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-38520721 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 38520721.

It is not an unprimeable number, because it can be changed into a prime (38520761) 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, 115165 + ... + 115498.

It is an arithmetic number, because the mean of its divisors is an integer number (9687888).

Almost surely, 2^38520721 is an apocalyptic number.

It is an amenable number.

38520721 is a deficient number, since it is larger than the sum of its proper divisors (230831).

38520721 is a wasteful number, since it uses less digits than its factorization.

38520721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230830.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 38520721 is about 6206.5063441521. The cubic root of 38520721 is about 337.7262380685.

The spelling of 38520721 in words is "thirty-eight million, five hundred twenty thousand, seven hundred twenty-one".