123215550 has 72 divisors (see below), whose sum is σ = 315953736. Its totient is φ = 31754880.

The previous prime is 123215549. The next prime is 123215581. The reversal of 123215550 is 55512321.

Added to its reverse (55512321) it gives a triangular number (178727871 = T₁₈₉₀₆).

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 123215550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 826876 + ... + 827024.

Almost surely, 2^123215550 is an apocalyptic number.

123215550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 123215550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157976868).

123215550 is an abundant number, since it is smaller than the sum of its proper divisors (192738186).

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

123215550 is a wasteful number, since it uses less digits than its factorization.

123215550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 123215550 is about 11100.2499971847. The cubic root of 123215550 is about 497.6093208579.

Adding to 123215550 its reverse (55512321), we get a palindrome (178727871).

It can be divided in two parts, 12321 and 5550, that added together give a palindrome (17871).

The spelling of 123215550 in words is "one hundred twenty-three million, two hundred fifteen thousand, five hundred fifty".