123129856 has 52 divisors (see below), whose sum is σ = 257131872. Its totient is φ = 58843136.

The previous prime is 123129829. The next prime is 123129871. The reversal of 123129856 is 658921321.

It is a super-2 number, since 2×123129856² = 30321922877161472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93555 + ... + 94861.

Almost surely, 2^123129856 is an apocalyptic number.

123129856 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 123129856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128565936).

123129856 is an abundant number, since it is smaller than the sum of its proper divisors (134002016).

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

123129856 is an equidigital number, since it uses as much as digits as its factorization.

123129856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354 (or 1332 counting only the distinct ones).

The product of its digits is 25920, while the sum is 37.

The square root of 123129856 is about 11096.3893226581. The cubic root of 123129856 is about 497.4939349277.

The spelling of 123129856 in words is "one hundred twenty-three million, one hundred twenty-nine thousand, eight hundred fifty-six".