172821768 has 64 divisors (see below), whose sum is σ = 495298560. Its totient is φ = 49225536.

The previous prime is 172821751. The next prime is 172821769. The reversal of 172821768 is 867128271.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (172821769) 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, 60255 + ... + 63057.

It is an arithmetic number, because the mean of its divisors is an integer number (7739040).

Almost surely, 2^172821768 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172821768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247649280).

172821768 is an abundant number, since it is smaller than the sum of its proper divisors (322476792).

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

172821768 is a wasteful number, since it uses less digits than its factorization.

172821768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3186 (or 3182 counting only the distinct ones).

The product of its digits is 75264, while the sum is 42.

The square root of 172821768 is about 13146.1693279830. The cubic root of 172821768 is about 557.0140475019.

The spelling of 172821768 in words is "one hundred seventy-two million, eight hundred twenty-one thousand, seven hundred sixty-eight".