231921 has 12 divisors (see below), whose sum is σ = 340548. Its totient is φ = 152064.

The previous prime is 231919. The next prime is 231923. The reversal of 231921 is 129132.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (231919) and next prime (231923).

It can be written as a sum of positive squares in 2 ways, for example, as 112896 + 119025 = 336^2 + 345^2 .

It is not a de Polignac number, because 231921 - 2¹ = 231919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231894 and 231903.

It is not an unprimeable number, because it can be changed into a prime (231923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 481 + ... + 833.

It is an arithmetic number, because the mean of its divisors is an integer number (28379).

2²³¹⁹²¹ is an apocalyptic number.

It is an amenable number.

231921 is a deficient number, since it is larger than the sum of its proper divisors (108627).

231921 is a wasteful number, since it uses less digits than its factorization.

231921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 429 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 231921 is about 481.5817687579. The cubic root of 231921 is about 61.4393612096.

The spelling of 231921 in words is "two hundred thirty-one thousand, nine hundred twenty-one".