231504021 has 16 divisors (see below), whose sum is σ = 391964800. Its totient is φ = 132287904.

The previous prime is 231503971. The next prime is 231504029. The reversal of 231504021 is 120405132.

It is not a de Polignac number, because 231504021 - 2⁶ = 231503957 is a prime.

It is a super-2 number, since 2×231504021² = 107188223478336882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 231503985 and 231504003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231504029) 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, 612256 + ... + 612633.

It is an arithmetic number, because the mean of its divisors is an integer number (24497800).

Almost surely, 2^231504021 is an apocalyptic number.

231504021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

231504021 is a deficient number, since it is larger than the sum of its proper divisors (160460779).

231504021 is a wasteful number, since it uses less digits than its factorization.

231504021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1224905 (or 1224899 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 231504021 is about 15215.2561923880. The cubic root of 231504021 is about 614.0251778377.

Adding to 231504021 its reverse (120405132), we get a palindrome (351909153).

The spelling of 231504021 in words is "two hundred thirty-one million, five hundred four thousand, twenty-one".