123640013281 has 2 divisors, whose sum is σ = 123640013282. Its totient is φ = 123640013280.

The previous prime is 123640013221. The next prime is 123640013293. The reversal of 123640013281 is 182310046321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66262997056 + 57377016225 = 257416^2 + 239535^2 .

It is a cyclic number.

It is not a de Polignac number, because 123640013281 - 2¹³ = 123640005089 is a prime.

It is a super-2 number, since 2×123640013281² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (123640013221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61820006640 + 61820006641.

It is an arithmetic number, because the mean of its divisors is an integer number (61820006641).

Almost surely, 2^123640013281 is an apocalyptic number.

It is an amenable number.

123640013281 is a deficient number, since it is larger than the sum of its proper divisors (1).

123640013281 is an equidigital number, since it uses as much as digits as its factorization.

123640013281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The spelling of 123640013281 in words is "one hundred twenty-three billion, six hundred forty million, thirteen thousand, two hundred eighty-one".