123999980 has 48 divisors (see below), whose sum is σ = 284027520. Its totient is φ = 45197568.

The previous prime is 123999979. The next prime is 123999983. The reversal of 123999980 is 89999321.

It is not an unprimeable number, because it can be changed into a prime (123999983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17522 + ... + 23558.

It is an arithmetic number, because the mean of its divisors is an integer number (5917240).

Almost surely, 2^123999980 is an apocalyptic number.

123999980 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 123999980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142013760).

123999980 is an abundant number, since it is smaller than the sum of its proper divisors (160027540).

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

123999980 is a wasteful number, since it uses less digits than its factorization.

123999980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6138 (or 6136 counting only the distinct ones).

The product of its (nonzero) digits is 314928, while the sum is 50.

The square root of 123999980 is about 11135.5278276335. The cubic root of 123999980 is about 498.6630684140.

The spelling of 123999980 in words is "one hundred twenty-three million, nine hundred ninety-nine thousand, nine hundred eighty".