209129689374489 has 45 divisors (see below), whose sum is σ = 338285935970829. Its totient is φ = 128694152246400.

The previous prime is 209129689374461. The next prime is 209129689374497. The reversal of 209129689374489 is 984473986921902.

The square root of 209129689374489 is 14461317.

It is a perfect power (a square), and thus also a powerful number.

209129689374489 is a `hidden beast` number, since 2 + 0 + 9 + 1 + 2 + 9 + 68 + 9 + 3 + 74 + 489 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 16077894575625 + 193051794798864 = 4009725^2 + 13894308^2 .

It is not a de Polignac number, because 209129689374489 - 2⁹ = 209129689373977 is a prime.

It is a super-2 number, since 2×209129689374489² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is not an unprimeable number, because it can be changed into a prime (209129689374409) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1691912289 + ... + 1692035889.

Almost surely, 2^{209129689374489} is an apocalyptic number.

209129689374489 is the 14461317-th square number.

209129689374489 is the 7230659-th centered octagonal number.

It is an amenable number.

209129689374489 is a deficient number, since it is larger than the sum of its proper divisors (129156246596340).

209129689374489 is an frugal number, since it uses more digits than its factorization.

209129689374489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247240 (or 123617 counting only the distinct ones).

The product of its (nonzero) digits is 3386105856, while the sum is 81.

209129689374489 divided by its sum of digits (81) gives a square (2581848016969 = 1606813²).

The spelling of 209129689374489 in words is "two hundred nine trillion, one hundred twenty-nine billion, six hundred eighty-nine million, three hundred seventy-four thousand, four hundred eighty-nine".