823131861 has 4 divisors (see below), whose sum is σ = 1097509152. Its totient is φ = 548754572.

The previous prime is 823131791. The next prime is 823131863. The reversal of 823131861 is 168131328.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 823131861 - 2¹⁴ = 823115477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (823131863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 137188641 + ... + 137188646.

It is an arithmetic number, because the mean of its divisors is an integer number (274377288).

Almost surely, 2^823131861 is an apocalyptic number.

It is an amenable number.

823131861 is a deficient number, since it is larger than the sum of its proper divisors (274377291).

823131861 is a wasteful number, since it uses less digits than its factorization.

823131861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274377290.

The product of its digits is 6912, while the sum is 33.

The square root of 823131861 is about 28690.2746762731. The cubic root of 823131861 is about 937.1802708461.

The spelling of 823131861 in words is "eight hundred twenty-three million, one hundred thirty-one thousand, eight hundred sixty-one".