12155786989 has 2 divisors, whose sum is σ = 12155786990. Its totient is φ = 12155786988.

The previous prime is 12155786983. The next prime is 12155787023. The reversal of 12155786989 is 98968755121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7794241225 + 4361545764 = 88285^2 + 66042^2 .

It is an emirp because it is prime and its reverse (98968755121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12155786989 - 2³³ = 3565852397 is a prime.

It is a super-2 number, since 2×12155786989² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12155786983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6077893494 + 6077893495.

It is an arithmetic number, because the mean of its divisors is an integer number (6077893495).

Almost surely, 2^12155786989 is an apocalyptic number.

It is an amenable number.

12155786989 is a deficient number, since it is larger than the sum of its proper divisors (1).

12155786989 is an equidigital number, since it uses as much as digits as its factorization.

12155786989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10886400, while the sum is 61.

The spelling of 12155786989 in words is "twelve billion, one hundred fifty-five million, seven hundred eighty-six thousand, nine hundred eighty-nine".