123218640 has 120 divisors (see below), whose sum is σ = 421747560. Its totient is φ = 32228352.

The previous prime is 123218639. The next prime is 123218647. The reversal of 123218640 is 46812321.

123218640 is a `hidden beast` number, since 1 + 2 + 3 + 2 + 18 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 13220496 + 109998144 = 3636^2 + 10488^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123218647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36546 + ... + 39774.

It is an arithmetic number, because the mean of its divisors is an integer number (3514563).

Almost surely, 2^123218640 is an apocalyptic number.

123218640 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 123218640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (210873780).

123218640 is an abundant number, since it is smaller than the sum of its proper divisors (298528920).

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

123218640 is a wasteful number, since it uses less digits than its factorization.

123218640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3301 (or 3292 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 123218640 is about 11100.3891823665. The cubic root of 123218640 is about 497.6134805059.

The spelling of 123218640 in words is "one hundred twenty-three million, two hundred eighteen thousand, six hundred forty".