123640400 has 180 divisors, whose sum is σ = 337656960. Its totient is φ = 43430400.

The previous prime is 123640381. The next prime is 123640403. The reversal of 123640400 is 4046321.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123640403) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2095571 + ... + 2095629.

It is an arithmetic number, because the mean of its divisors is an integer number (1875872).

Almost surely, 2^123640400 is an apocalyptic number.

123640400 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 123640400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (168828480).

123640400 is an abundant number, since it is smaller than the sum of its proper divisors (214016560).

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

123640400 is a wasteful number, since it uses less digits than its factorization.

123640400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 123640400 is about 11119.3704857784. The cubic root of 123640400 is about 498.1805875067.

Adding to 123640400 its reverse (4046321), we get a palindrome (127686721).

The spelling of 123640400 in words is "one hundred twenty-three million, six hundred forty thousand, four hundred".