1155827989 has 2 divisors, whose sum is σ = 1155827990. Its totient is φ = 1155827988.

The previous prime is 1155827987. The next prime is 1155828013. The reversal of 1155827989 is 9897285511.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 705327364 + 450500625 = 26558^2 + 21225^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155827989 - 2¹ = 1155827987 is a prime.

Together with 1155827987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1155827987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 577913994 + 577913995.

It is an arithmetic number, because the mean of its divisors is an integer number (577913995).

Almost surely, 2^1155827989 is an apocalyptic number.

It is an amenable number.

1155827989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1155827989 is an equidigital number, since it uses as much as digits as its factorization.

1155827989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1814400, while the sum is 55.

The square root of 1155827989 is about 33997.4703323644. The cubic root of 1155827989 is about 1049.4564046405.

The spelling of 1155827989 in words is "one billion, one hundred fifty-five million, eight hundred twenty-seven thousand, nine hundred eighty-nine".