123215640 has 64 divisors (see below), whose sum is σ = 378259200. Its totient is φ = 32092032.

The previous prime is 123215633. The next prime is 123215663. The reversal of 123215640 is 46512321.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 123215640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6780 + ... + 17099.

It is an arithmetic number, because the mean of its divisors is an integer number (5910300).

Almost surely, 2^123215640 is an apocalyptic number.

123215640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123215640 is an abundant number, since it is smaller than the sum of its proper divisors (255043560).

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

123215640 is a wasteful number, since it uses less digits than its factorization.

123215640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23936 (or 23932 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 123215640 is about 11100.2540511468. The cubic root of 123215640 is about 497.6094420137.

Adding to 123215640 its reverse (46512321), we get a palindrome (169727961).

The spelling of 123215640 in words is "one hundred twenty-three million, two hundred fifteen thousand, six hundred forty".