231287821 has 8 divisors (see below), whose sum is σ = 233086464. Its totient is φ = 229495680.

The previous prime is 231287809. The next prime is 231287827. The reversal of 231287821 is 128782132.

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

It is a cyclic number.

It is not a de Polignac number, because 231287821 - 2¹¹ = 231285773 is a prime.

It is a super-2 number, since 2×231287821² = 106988112285856082, 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 (231287827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87901 + ... + 90493.

It is an arithmetic number, because the mean of its divisors is an integer number (29135808).

Almost surely, 2^231287821 is an apocalyptic number.

It is an amenable number.

231287821 is a deficient number, since it is larger than the sum of its proper divisors (1798643).

231287821 is a wasteful number, since it uses less digits than its factorization.

231287821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3251.

The product of its digits is 10752, while the sum is 34.

The square root of 231287821 is about 15208.1498217239. The cubic root of 231287821 is about 613.8339736852.

The spelling of 231287821 in words is "two hundred thirty-one million, two hundred eighty-seven thousand, eight hundred twenty-one".