172639728 has 80 divisors (see below), whose sum is σ = 499328160. Its totient is φ = 57106944.

The previous prime is 172639717. The next prime is 172639729. The reversal of 172639728 is 827936271.

172639728 is a `hidden beast` number, since 1 + 7 + 2 + 639 + 7 + 2 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172639729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57726 + ... + 60642.

It is an arithmetic number, because the mean of its divisors is an integer number (6241602).

Almost surely, 2^172639728 is an apocalyptic number.

172639728 is a gapful number since it is divisible by the number (18) 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 172639728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249664080).

172639728 is an abundant number, since it is smaller than the sum of its proper divisors (326688432).

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

172639728 is a wasteful number, since it uses less digits than its factorization.

172639728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3071 (or 3059 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 172639728 is about 13139.2438138578. The cubic root of 172639728 is about 556.8184038209.

The spelling of 172639728 in words is "one hundred seventy-two million, six hundred thirty-nine thousand, seven hundred twenty-eight".