172205520 has 80 divisors (see below), whose sum is σ = 535144320. Its totient is φ = 45809152.

The previous prime is 172205519. The next prime is 172205573. The reversal of 172205520 is 25502271.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×172205520² = 59309482236940800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154726 + ... + 155834.

It is an arithmetic number, because the mean of its divisors is an integer number (6689304).

Almost surely, 2^172205520 is an apocalyptic number.

172205520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172205520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267572160).

172205520 is an abundant number, since it is smaller than the sum of its proper divisors (362938800).

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

172205520 is a wasteful number, since it uses less digits than its factorization.

172205520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1772 (or 1766 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 172205520 is about 13122.7100859540. The cubic root of 172205520 is about 556.3511919593.

Adding to 172205520 its reverse (25502271), we get a palindrome (197707791).

The spelling of 172205520 in words is "one hundred seventy-two million, two hundred five thousand, five hundred twenty".