165724710649 has 9 divisors (see below), whose sum is σ = 168932583309. Its totient is φ = 162576660480.

The previous prime is 165724710643. The next prime is 165724710691. The reversal of 165724710649 is 946017427561.

The square root of 165724710649 is 407093.

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

It can be written as a sum of positive squares in 4 ways, for example, as 29513522025 + 136211188624 = 171795^2 + 369068^2 .

It is not a de Polignac number, because 165724710649 - 2⁷ = 165724710521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165724710596 and 165724710605.

It is not an unprimeable number, because it can be changed into a prime (165724710643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 21572089 + ... + 21579769.

Almost surely, 2^165724710649 is an apocalyptic number.

165724710649 is the 407093-rd square number.

165724710649 is the 203547-th centered octagonal number.

It is an amenable number.

165724710649 is a deficient number, since it is larger than the sum of its proper divisors (3207872660).

165724710649 is an frugal number, since it uses more digits than its factorization.

165724710649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15468 (or 7734 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 52.

The spelling of 165724710649 in words is "one hundred sixty-five billion, seven hundred twenty-four million, seven hundred ten thousand, six hundred forty-nine".