123049187981 has 2 divisors, whose sum is σ = 123049187982. Its totient is φ = 123049187980.

The previous prime is 123049187929. The next prime is 123049188019. The reversal of 123049187981 is 189781940321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115351933225 + 7697254756 = 339635^2 + 87734^2 .

It is an emirp because it is prime and its reverse (189781940321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123049187981 - 2¹⁸ = 123048925837 is a prime.

It is a super-2 number, since 2×123049187981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123049187281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61524593990 + 61524593991.

It is an arithmetic number, because the mean of its divisors is an integer number (61524593991).

Almost surely, 2^123049187981 is an apocalyptic number.

It is an amenable number.

123049187981 is a deficient number, since it is larger than the sum of its proper divisors (1).

123049187981 is an equidigital number, since it uses as much as digits as its factorization.

123049187981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 870912, while the sum is 53.

The spelling of 123049187981 in words is "one hundred twenty-three billion, forty-nine million, one hundred eighty-seven thousand, nine hundred eighty-one".