1389201991 has 2 divisors, whose sum is σ = 1389201992. Its totient is φ = 1389201990.

The previous prime is 1389201949. The next prime is 1389202013. The reversal of 1389201991 is 1991029831.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1389201991 - 2¹¹ = 1389199943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1389201911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694600995 + 694600996.

It is an arithmetic number, because the mean of its divisors is an integer number (694600996).

Almost surely, 2^1389201991 is an apocalyptic number.

1389201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1389201991 is an equidigital number, since it uses as much as digits as its factorization.

1389201991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 1389201991 is about 37272.0000939043. Note that the first 4 decimals coincide. The cubic root of 1389201991 is about 1115.8054175189.

The spelling of 1389201991 in words is "one billion, three hundred eighty-nine million, two hundred one thousand, nine hundred ninety-one".