123666261631616 has 128 divisors (see below), whose sum is σ = 273778200097920. Its totient is φ = 55632425164800.

The previous prime is 123666261631543. The next prime is 123666261631621. The reversal of 123666261631616 is 616136162666321.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×123666261631616² (a number of 29 digits) contains 22 as substring.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 12784061 + ... + 20267331.

It is an arithmetic number, because the mean of its divisors is an integer number (2138892188265).

Almost surely, 2^{123666261631616} is an apocalyptic number.

123666261631616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 123666261631616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136889100048960).

123666261631616 is an abundant number, since it is smaller than the sum of its proper divisors (150111938466304).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

123666261631616 is an frugal number, since it uses more digits than its factorization.

123666261631616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7483415 (or 7483381 counting only the distinct ones).

The product of its digits is 10077696, while the sum is 56.

The spelling of 123666261631616 in words is "one hundred twenty-three trillion, six hundred sixty-six billion, two hundred sixty-one million, six hundred thirty-one thousand, six hundred sixteen".