123172123920 has 80 divisors (see below), whose sum is σ = 394150820352. Its totient is φ = 31786352640.

The previous prime is 123172123873. The next prime is 123172123927. The reversal of 123172123920 is 29321271321.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×123172123920² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (123172123927) 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 15 ways as a sum of consecutive naturals, for example, 8270257 + ... + 8285136.

Almost surely, 2^123172123920 is an apocalyptic number.

123172123920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123172123920 is an abundant number, since it is smaller than the sum of its proper divisors (270978696432).

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

123172123920 is a wasteful number, since it uses less digits than its factorization.

123172123920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16555440 (or 16555434 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 33.

The spelling of 123172123920 in words is "one hundred twenty-three billion, one hundred seventy-two million, one hundred twenty-three thousand, nine hundred twenty".