38666721 has 16 divisors (see below), whose sum is σ = 54960768. Its totient is φ = 24096000.

The previous prime is 38666701. The next prime is 38666723. The reversal of 38666721 is 12766683.

It is not a de Polignac number, because 38666721 - 2⁵ = 38666689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 38666721.

It is not an unprimeable number, because it can be changed into a prime (38666723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5191 + ... + 10211.

It is an arithmetic number, because the mean of its divisors is an integer number (3435048).

Almost surely, 2^38666721 is an apocalyptic number.

It is an amenable number.

38666721 is a deficient number, since it is larger than the sum of its proper divisors (16294047).

38666721 is a wasteful number, since it uses less digits than its factorization.

38666721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5192.

The product of its digits is 72576, while the sum is 39.

The square root of 38666721 is about 6218.2570709163. The cubic root of 38666721 is about 338.1523798530.

The spelling of 38666721 in words is "thirty-eight million, six hundred sixty-six thousand, seven hundred twenty-one".