1389471581 has 2 divisors, whose sum is σ = 1389471582. Its totient is φ = 1389471580.

The previous prime is 1389471533. The next prime is 1389471593. The reversal of 1389471581 is 1851749831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1364120356 + 25351225 = 36934^2 + 5035^2 .

It is an emirp because it is prime and its reverse (1851749831) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1389471581 is a prime.

It is a super-2 number, since 2×1389471581² = 3861262548813279122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1389471511) 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 as a sum of consecutive naturals, namely, 694735790 + 694735791.

It is an arithmetic number, because the mean of its divisors is an integer number (694735791).

Almost surely, 2^1389471581 is an apocalyptic number.

It is an amenable number.

1389471581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1389471581 is an equidigital number, since it uses as much as digits as its factorization.

1389471581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 47.

The square root of 1389471581 is about 37275.6164402415. The cubic root of 1389471581 is about 1115.8775909748.

The spelling of 1389471581 in words is "one billion, three hundred eighty-nine million, four hundred seventy-one thousand, five hundred eighty-one".