821282728 has 24 divisors (see below), whose sum is σ = 1791319050. Its totient is φ = 351978144.

The previous prime is 821282701. The next prime is 821282729. The reversal of 821282728 is 827282128.

It can be written as a sum of positive squares in only one way, i.e., 821280964 + 1764 = 28658^2 + 42^2 .

It is a super-2 number, since 2×821282728² = 1349010638622243968, which contains 22 as substring.

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 (821282729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1047163 + ... + 1047946.

Almost surely, 2^821282728 is an apocalyptic number.

It is an amenable number.

821282728 is an abundant number, since it is smaller than the sum of its proper divisors (970036322).

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

821282728 is a wasteful number, since it uses less digits than its factorization.

821282728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2095129 (or 2095118 counting only the distinct ones).

The product of its digits is 57344, while the sum is 40.

The square root of 821282728 is about 28658.0307767299. The cubic root of 821282728 is about 936.4779652766.

The spelling of 821282728 in words is "eight hundred twenty-one million, two hundred eighty-two thousand, seven hundred twenty-eight".