123658640 has 80 divisors (see below), whose sum is σ = 329978880. Its totient is φ = 42216960.

The previous prime is 123658589. The next prime is 123658763. The reversal of 123658640 is 46856321.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 123658640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 257921 + ... + 258399.

It is an arithmetic number, because the mean of its divisors is an integer number (4124736).

Almost surely, 2^123658640 is an apocalyptic number.

123658640 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 123658640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (164989440).

123658640 is an abundant number, since it is smaller than the sum of its proper divisors (206320240).

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

123658640 is a wasteful number, since it uses less digits than its factorization.

With its successor (123658641) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (954).

123658640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960 (or 954 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 123658640 is about 11120.1906458478. The cubic root of 123658640 is about 498.2050842653.

The spelling of 123658640 in words is "one hundred twenty-three million, six hundred fifty-eight thousand, six hundred forty".