231613821 has 24 divisors (see below), whose sum is σ = 345246720. Its totient is φ = 149514336.

The previous prime is 231613801. The next prime is 231613847. The reversal of 231613821 is 128316132.

It is a happy number.

231613821 is a `hidden beast` number, since 23 + 1 + 613 + 8 + 21 = 666.

It is not a de Polignac number, because 231613821 - 2⁶ = 231613757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231613801) 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 23 ways as a sum of consecutive naturals, for example, 72700 + ... + 75818.

It is an arithmetic number, because the mean of its divisors is an integer number (14385280).

Almost surely, 2^231613821 is an apocalyptic number.

It is an amenable number.

231613821 is a deficient number, since it is larger than the sum of its proper divisors (113632899).

231613821 is a wasteful number, since it uses less digits than its factorization.

231613821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3385 (or 3382 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 231613821 is about 15218.8639851994. The cubic root of 231613821 is about 614.1222377911.

Adding to 231613821 its reverse (128316132), we get a palindrome (359929953).

The spelling of 231613821 in words is "two hundred thirty-one million, six hundred thirteen thousand, eight hundred twenty-one".