1389137221 has 4 divisors (see below), whose sum is σ = 1408166572. Its totient is φ = 1370107872.

The previous prime is 1389137203. The next prime is 1389137273. The reversal of 1389137221 is 1227319831.

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 447322500 + 941814721 = 21150^2 + 30689^2 .

It is a cyclic number.

It is not a de Polignac number, because 1389137221 - 2¹⁷ = 1389006149 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 (1389137921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9514566 + ... + 9514711.

It is an arithmetic number, because the mean of its divisors is an integer number (352041643).

Almost surely, 2^1389137221 is an apocalyptic number.

It is an amenable number.

1389137221 is a deficient number, since it is larger than the sum of its proper divisors (19029351).

1389137221 is an equidigital number, since it uses as much as digits as its factorization.

1389137221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19029350.

The product of its digits is 18144, while the sum is 37.

The square root of 1389137221 is about 37271.1312009711. The cubic root of 1389137221 is about 1115.7880761866.

The spelling of 1389137221 in words is "one billion, three hundred eighty-nine million, one hundred thirty-seven thousand, two hundred twenty-one".