1389742561 has 2 divisors, whose sum is σ = 1389742562. Its totient is φ = 1389742560.

The previous prime is 1389742559. The next prime is 1389742637. The reversal of 1389742561 is 1652479831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1311526225 + 78216336 = 36215^2 + 8844^2 .

It is a cyclic number.

It is not a de Polignac number, because 1389742561 - 2¹ = 1389742559 is a prime.

Together with 1389742559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1389742531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694871280 + 694871281.

It is an arithmetic number, because the mean of its divisors is an integer number (694871281).

Almost surely, 2^1389742561 is an apocalyptic number.

It is an amenable number.

1389742561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1389742561 is an equidigital number, since it uses as much as digits as its factorization.

1389742561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 46.

The square root of 1389742561 is about 37279.2510788508. The cubic root of 1389742561 is about 1115.9501271482.

The spelling of 1389742561 in words is "one billion, three hundred eighty-nine million, seven hundred forty-two thousand, five hundred sixty-one".