123112031981 has 2 divisors, whose sum is σ = 123112031982. Its totient is φ = 123112031980.

The previous prime is 123112031969. The next prime is 123112032067. The reversal of 123112031981 is 189130211321.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81858359881 + 41253672100 = 286109^2 + 203110^2 .

It is a cyclic number.

It is not a de Polignac number, because 123112031981 - 2²⁶ = 123044923117 is a prime.

It is a super-3 number, since 3×123112031981³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123112031681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61556015990 + 61556015991.

It is an arithmetic number, because the mean of its divisors is an integer number (61556015991).

Almost surely, 2^123112031981 is an apocalyptic number.

It is an amenable number.

123112031981 is a deficient number, since it is larger than the sum of its proper divisors (1).

123112031981 is an equidigital number, since it uses as much as digits as its factorization.

123112031981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 32.

The spelling of 123112031981 in words is "one hundred twenty-three billion, one hundred twelve million, thirty-one thousand, nine hundred eighty-one".