123816347981 has 4 divisors (see below), whose sum is σ = 123936442464. Its totient is φ = 123696253500.

The previous prime is 123816347957. The next prime is 123816347983. The reversal of 123816347981 is 189743618321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 189743618321 = 17 ⋅11161389313.

It is a cyclic number.

It is not a de Polignac number, because 123816347981 - 2¹⁰ = 123816346957 is a prime.

It is a super-2 number, since 2×123816347981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123816347983) 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 in 3 ways as a sum of consecutive naturals, for example, 60045695 + ... + 60047756.

It is an arithmetic number, because the mean of its divisors is an integer number (30984110616).

Almost surely, 2^123816347981 is an apocalyptic number.

It is an amenable number.

123816347981 is a deficient number, since it is larger than the sum of its proper divisors (120094483).

123816347981 is a wasteful number, since it uses less digits than its factorization.

123816347981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120094482.

The product of its digits is 1741824, while the sum is 53.

The spelling of 123816347981 in words is "one hundred twenty-three billion, eight hundred sixteen million, three hundred forty-seven thousand, nine hundred eighty-one".