2169729 has 9 divisors (see below), whose sum is σ = 3140449.
Its totient is φ = 1443540.
The previous prime is 2169707. The next prime is 2169749. The reversal of 2169729 is 9279612.
The square root of 2169729 is 1473.
It is a perfect power (a square), and thus also a powerful number.
It is a tau number, because it is divible by the number of its divisors (9).
It is not a de Polignac number, because 2169729 - 221 = 72577 is a prime.
It is a Duffinian number.
It is a Curzon number.
It is a junction number, because it is equal to n+sod(n) for n = 2169693 and 2169702.
It is not an unprimeable number, because it can be changed into a prime (2169749) by changing a digit.
It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4174 + ... + 4664.
22169729 is an apocalyptic number.
2169729 is the 1473-rd square number.
2169729 is the 737-th centered octagonal number.
It is an amenable number.
2169729 is a deficient number, since it is larger than the sum of its proper divisors (970720).
2169729 is an frugal number, since it uses more digits than its factorization.
2169729 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 988 (or 494 counting only the distinct ones).
The product of its digits is 13608, while the sum is 36.
The cubic root of 2169729 is about 129.4598693997.
Multiplying 2169729 by its sum of digits (36), we get a square (78110244 = 88382).
The spelling of 2169729 in words is "two million, one hundred sixty-nine thousand, seven hundred twenty-nine".