821000172 has 12 divisors (see below), whose sum is σ = 1915667096. Its totient is φ = 273666720.

The previous prime is 821000129. The next prime is 821000177. The reversal of 821000172 is 271000128.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (821000177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34208329 + ... + 34208352.

Almost surely, 2^821000172 is an apocalyptic number.

It is an amenable number.

821000172 is an abundant number, since it is smaller than the sum of its proper divisors (1094666924).

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

821000172 is a wasteful number, since it uses less digits than its factorization.

821000172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68416688 (or 68416686 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 821000172 is about 28653.1005652093. The cubic root of 821000172 is about 936.3705569465.

The spelling of 821000172 in words is "eight hundred twenty-one million, one hundred seventy-two", and thus it is an aban number.