It is a congruent number.
It is an unprimeable number.
Almost surely, 2122121216 is an apocalyptic number.
122121216 is a gapful number since it is divisible by the number (16) 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 122121216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206992640).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
122121216 is an equidigital number, since it uses as much as digits as its factorization.
122121216 is an odious number, because the sum of its binary digits is odd.
The square root of 122121216 is about 11050.8468453780. The cubic root of 122121216 is about 496.1317721344.
Adding to 122121216 its reverse (612121221), we get a palindrome (734242437).
The spelling of 122121216 in words is "one hundred twenty-two million, one hundred twenty-one thousand, two hundred sixteen".