123398640 has 200 divisors, whose sum is σ = 434815920. Its totient is φ = 32431104.

The previous prime is 123398629. The next prime is 123398659. The reversal of 123398640 is 46893321.

123398640 is a `hidden beast` number, since 1 + 2 + 3 + 3 + 9 + 8 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 123398595 and 123398604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 887691 + ... + 887829.

Almost surely, 2^123398640 is an apocalyptic number.

123398640 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 123398640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217407960).

123398640 is an abundant number, since it is smaller than the sum of its proper divisors (311417280).

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

123398640 is a wasteful number, since it uses less digits than its factorization.

123398640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 286 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 123398640 is about 11108.4940473495. The cubic root of 123398640 is about 497.8556701792.

The spelling of 123398640 in words is "one hundred twenty-three million, three hundred ninety-eight thousand, six hundred forty".