831543661 has 16 divisors (see below), whose sum is σ = 973821744. Its totient is φ = 702895104.

The previous prime is 831543649. The next prime is 831543697. The reversal of 831543661 is 166345138.

It can be written as a sum of positive squares in 8 ways, for example, as 2449225 + 829094436 = 1565^2 + 28794^2 .

It is a cyclic number.

It is not a de Polignac number, because 831543661 - 2¹⁵ = 831510893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 831543661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (831543611) 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, 42670 + ... + 59023.

It is an arithmetic number, because the mean of its divisors is an integer number (60863859).

Almost surely, 2^831543661 is an apocalyptic number.

It is an amenable number.

831543661 is a deficient number, since it is larger than the sum of its proper divisors (142278083).

831543661 is a wasteful number, since it uses less digits than its factorization.

831543661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101760.

The product of its digits is 51840, while the sum is 37.

The square root of 831543661 is about 28836.4987645865. The cubic root of 831543661 is about 940.3618875954.

Adding to 831543661 its reverse (166345138), we get a palindrome (997888799).

The spelling of 831543661 in words is "eight hundred thirty-one million, five hundred forty-three thousand, six hundred sixty-one".