123131009 has 2 divisors, whose sum is σ = 123131010. Its totient is φ = 123131008.

The previous prime is 123130993. The next prime is 123131033. The reversal of 123131009 is 900131321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109830400 + 13300609 = 10480^2 + 3647^2 .

It is an emirp because it is prime and its reverse (900131321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123131009 - 2⁴ = 123130993 is a prime.

It is a super-2 number, since 2×123131009² = 30322490754716162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (123131809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61565504 + 61565505.

It is an arithmetic number, because the mean of its divisors is an integer number (61565505).

Almost surely, 2^123131009 is an apocalyptic number.

It is an amenable number.

123131009 is a deficient number, since it is larger than the sum of its proper divisors (1).

123131009 is an equidigital number, since it uses as much as digits as its factorization.

123131009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 123131009 is about 11096.4412763732. The cubic root of 123131009 is about 497.4954877835.

The spelling of 123131009 in words is "one hundred twenty-three million, one hundred thirty-one thousand, nine".