172505805 has 16 divisors (see below), whose sum is σ = 276799680. Its totient is φ = 91739648.

The previous prime is 172505779. The next prime is 172505821. The reversal of 172505805 is 508505271.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 172505805 - 2⁸ = 172505549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10995 + ... + 21584.

It is an arithmetic number, because the mean of its divisors is an integer number (17299980).

Almost surely, 2^172505805 is an apocalyptic number.

172505805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

172505805 is a deficient number, since it is larger than the sum of its proper divisors (104293875).

172505805 is a wasteful number, since it uses less digits than its factorization.

172505805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32940.

The product of its (nonzero) digits is 14000, while the sum is 33.

The square root of 172505805 is about 13134.1465272777. The cubic root of 172505805 is about 556.6743850548.

The spelling of 172505805 in words is "one hundred seventy-two million, five hundred five thousand, eight hundred five".