172856820 has 96 divisors (see below), whose sum is σ = 513112320. Its totient is φ = 43402240.

The previous prime is 172856809. The next prime is 172856821. The reversal of 172856820 is 28658271.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172856821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70129 + ... + 72551.

It is an arithmetic number, because the mean of its divisors is an integer number (5344920).

Almost surely, 2^172856820 is an apocalyptic number.

172856820 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 172856820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256556160).

172856820 is an abundant number, since it is smaller than the sum of its proper divisors (340255500).

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

172856820 is a wasteful number, since it uses less digits than its factorization.

172856820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2505 (or 2503 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 39.

The square root of 172856820 is about 13147.5024244151. The cubic root of 172856820 is about 557.0517031298.

The spelling of 172856820 in words is "one hundred seventy-two million, eight hundred fifty-six thousand, eight hundred twenty".