165273958521 has 99 divisors (see below), whose sum is σ = 289596243621. Its totient is φ = 94047106104.

The previous prime is 165273958511. The next prime is 165273958529. The reversal of 165273958521 is 125859372561.

The square root of 165273958521 is 406539.

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

165273958521 is a `hidden beast` number, since 1 + 6 + 5 + 2 + 7 + 39 + 585 + 21 = 666.

It is not a de Polignac number, because 165273958521 - 2⁵ = 165273958489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165273958529) by changing a digit.

It is a polite number, since it can be written in 98 ways as a sum of consecutive naturals, for example, 691522720 + ... + 691522958.

Almost surely, 2^165273958521 is an apocalyptic number.

165273958521 is the 406539-th square number.

165273958521 is the 203270-th centered octagonal number.

It is an amenable number.

165273958521 is a deficient number, since it is larger than the sum of its proper divisors (124322285100).

165273958521 is an frugal number, since it uses more digits than its factorization.

165273958521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 249 counting only the distinct ones).

The product of its digits is 4536000, while the sum is 54.

The spelling of 165273958521 in words is "one hundred sixty-five billion, two hundred seventy-three million, nine hundred fifty-eight thousand, five hundred twenty-one".