123581879991 has 24 divisors (see below), whose sum is σ = 186413026176. Its totient is φ = 78744623760.

The previous prime is 123581879969. The next prime is 123581880011. The reversal of 123581879991 is 199978185321.

123581879991 is a `hidden beast` number, since 12 + 358 + 187 + 9 + 9 + 91 = 666.

It is not a de Polignac number, because 123581879991 - 2⁹ = 123581879479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123581879951) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36016 + ... + 498458.

It is an arithmetic number, because the mean of its divisors is an integer number (7767209424).

Almost surely, 2^123581879991 is an apocalyptic number.

123581879991 is a deficient number, since it is larger than the sum of its proper divisors (62831146185).

123581879991 is a wasteful number, since it uses less digits than its factorization.

123581879991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463763 (or 463760 counting only the distinct ones).

The product of its digits is 9797760, while the sum is 63.

The spelling of 123581879991 in words is "one hundred twenty-three billion, five hundred eighty-one million, eight hundred seventy-nine thousand, nine hundred ninety-one".