172505820 has 24 divisors (see below), whose sum is σ = 483016464. Its totient is φ = 46001536.

The previous prime is 172505779. The next prime is 172505821. The reversal of 172505820 is 28505271.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172505821) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1437489 + ... + 1437608.

It is an arithmetic number, because the mean of its divisors is an integer number (20125686).

Almost surely, 2^172505820 is an apocalyptic number.

172505820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

172505820 is an abundant number, since it is smaller than the sum of its proper divisors (310510644).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

172505820 is a wasteful number, since it uses less digits than its factorization.

172505820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2875109 (or 2875107 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 172505820 is about 13134.1470983083. The cubic root of 172505820 is about 556.6744011897.

The spelling of 172505820 in words is "one hundred seventy-two million, five hundred five thousand, eight hundred twenty".