821865471 has 8 divisors (see below), whose sum is σ = 1252366464. Its totient is φ = 469637400.

The previous prime is 821865461. The next prime is 821865491. The reversal of 821865471 is 174568128.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 821865471 - 2¹¹ = 821863423 is a prime.

It is a super-3 number, since 3×821865471³ (a number of 28 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821865461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19568205 + ... + 19568246.

It is an arithmetic number, because the mean of its divisors is an integer number (156545808).

Almost surely, 2^821865471 is an apocalyptic number.

821865471 is a deficient number, since it is larger than the sum of its proper divisors (430500993).

821865471 is a wasteful number, since it uses less digits than its factorization.

821865471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39136461.

The product of its digits is 107520, while the sum is 42.

The square root of 821865471 is about 28668.1961588099. The cubic root of 821865471 is about 936.6994062565.

The spelling of 821865471 in words is "eight hundred twenty-one million, eight hundred sixty-five thousand, four hundred seventy-one".