123640220 has 72 divisors (see below), whose sum is σ = 300526800. Its totient is φ = 42577920.

The previous prime is 123640219. The next prime is 123640243. The reversal of 123640220 is 22046321.

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

It is a junction number, because it is equal to n+sod(n) for n = 123640192 and 123640201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44636 + ... + 47324.

Almost surely, 2^123640220 is an apocalyptic number.

123640220 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 123640220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150263400).

123640220 is an abundant number, since it is smaller than the sum of its proper divisors (176886580).

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

123640220 is a wasteful number, since it uses less digits than its factorization.

123640220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2739 (or 2726 counting only the distinct ones).

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

The square root of 123640220 is about 11119.3623917921. The cubic root of 123640220 is about 498.1803457503.

Adding to 123640220 its reverse (22046321), we get a palindrome (145686541).

The spelling of 123640220 in words is "one hundred twenty-three million, six hundred forty thousand, two hundred twenty".