231040021 has 4 divisors (see below), whose sum is σ = 233283232. Its totient is φ = 228796812.

The previous prime is 231040009. The next prime is 231040027. The reversal of 231040021 is 120040132.

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 231040021 - 2¹⁵ = 231007253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231039983 and 231040010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231040027) 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 3 ways as a sum of consecutive naturals, for example, 1121451 + ... + 1121656.

It is an arithmetic number, because the mean of its divisors is an integer number (58320808).

Almost surely, 2^231040021 is an apocalyptic number.

It is an amenable number.

231040021 is a deficient number, since it is larger than the sum of its proper divisors (2243211).

231040021 is a wasteful number, since it uses less digits than its factorization.

231040021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2243210.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 231040021 is about 15200.0006907895. Note that the first 3 decimals coincide. The cubic root of 231040021 is about 613.6146763427.

Adding to 231040021 its reverse (120040132), we get a palindrome (351080153).

The spelling of 231040021 in words is "two hundred thirty-one million, forty thousand, twenty-one".