165512221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a Duffinian number.
It is a congruent number.
Almost surely, 2165512221 is an apocalyptic number.
It is an amenable number.
165512221 is a wasteful number, since it uses less digits than its factorization.
165512221 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1390883.
The square root of 165512221 is about 12865.1553041539. The cubic root of 165512221 is about 549.0476311882.
Adding to 165512221 its reverse (122215561), we get a palindrome (287727782).
The spelling of 165512221 in words is "one hundred sixty-five million, five hundred twelve thousand, two hundred twenty-one".