820831631 has 4 divisors (see below), whose sum is σ = 849136200. Its totient is φ = 792527064.

The previous prime is 820831591. The next prime is 820831703. The reversal of 820831631 is 136138028.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 820831631 - 2¹⁸ = 820569487 is a prime.

It is a super-2 number, since 2×820831631² = 1347529132900240322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820831031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14152241 + ... + 14152298.

It is an arithmetic number, because the mean of its divisors is an integer number (212284050).

Almost surely, 2^820831631 is an apocalyptic number.

820831631 is a deficient number, since it is larger than the sum of its proper divisors (28304569).

820831631 is a wasteful number, since it uses less digits than its factorization.

820831631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28304568.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 820831631 is about 28650.1593538326. The cubic root of 820831631 is about 936.3064775322.

Adding to 820831631 its reverse (136138028), we get a palindrome (956969659).

The spelling of 820831631 in words is "eight hundred twenty million, eight hundred thirty-one thousand, six hundred thirty-one".