389500021 has 4 divisors (see below), whose sum is σ = 396849132. Its totient is φ = 382150912.

The previous prime is 389500003. The next prime is 389500031. The reversal of 389500021 is 120005983.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120005983 = 127 ⋅944929.

It can be written as a sum of positive squares in 2 ways, for example, as 328878225 + 60621796 = 18135^2 + 7786^2 .

It is a cyclic number.

It is not a de Polignac number, because 389500021 - 2¹¹ = 389497973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (389500031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3674476 + ... + 3674581.

It is an arithmetic number, because the mean of its divisors is an integer number (99212283).

Almost surely, 2^389500021 is an apocalyptic number.

It is an amenable number.

389500021 is a deficient number, since it is larger than the sum of its proper divisors (7349111).

389500021 is an equidigital number, since it uses as much as digits as its factorization.

389500021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7349110.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 389500021 is about 19735.7548880199. The cubic root of 389500021 is about 730.3020086472.

It can be divided in two parts, 38 and 9500021, that added together give a palindrome (9500059).

The spelling of 389500021 in words is "three hundred eighty-nine million, five hundred thousand, twenty-one".