123721920 has 504 divisors, whose sum is σ = 543482784. Its totient is φ = 25214976.

The previous prime is 123721891. The next prime is 123721931. The reversal of 123721920 is 29127321.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-2 number, since 2×123721920² = 30614226976972800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 6511671 + ... + 6511689.

Almost surely, 2^123721920 is an apocalyptic number.

123721920 is a gapful number since it is divisible by the number (10) 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 123721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (271741392).

123721920 is an abundant number, since it is smaller than the sum of its proper divisors (419760864).

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

123721920 is a wasteful number, since it uses less digits than its factorization.

123721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 123721920 is about 11123.0355568972. The cubic root of 123721920 is about 498.2900521564.

The spelling of 123721920 in words is "one hundred twenty-three million, seven hundred twenty-one thousand, nine hundred twenty".