166078255729 has 3 divisors (see below), whose sum is σ = 166078663257. Its totient is φ = 166077848202.

The previous prime is 166078255709. The next prime is 166078255747. The reversal of 166078255729 is 927552870661.

The square root of 166078255729 is 407527.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 927552870661 = 252289 ⋅3676549.

It is not a de Polignac number, because 166078255729 - 2¹¹ = 166078253681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166078255709) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 203764 + ... + 611290.

It is an arithmetic number, because the mean of its divisors is an integer number (55359554419).

Almost surely, 2^166078255729 is an apocalyptic number.

166078255729 is the 407527-th square number.

166078255729 is the 203764-th centered octagonal number.

It is an amenable number.

166078255729 is a deficient number, since it is larger than the sum of its proper divisors (407528).

166078255729 is an frugal number, since it uses more digits than its factorization.

166078255729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815054 (or 407527 counting only the distinct ones).

The product of its (nonzero) digits is 12700800, while the sum is 58.

The spelling of 166078255729 in words is "one hundred sixty-six billion, seventy-eight million, two hundred fifty-five thousand, seven hundred twenty-nine".