231280921 has 4 divisors (see below), whose sum is σ = 231326244. Its totient is φ = 231235600.

The previous prime is 231280919. The next prime is 231280927. The reversal of 231280921 is 129082132.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 87160896 + 144120025 = 9336^2 + 12005^2 .

It is a cyclic number.

It is not a de Polignac number, because 231280921 - 2¹ = 231280919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 231280921.

It is not an unprimeable number, because it can be changed into a prime (231280927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13870 + ... + 25591.

It is an arithmetic number, because the mean of its divisors is an integer number (57831561).

Almost surely, 2^231280921 is an apocalyptic number.

It is an amenable number.

231280921 is a deficient number, since it is larger than the sum of its proper divisors (45323).

231280921 is an equidigital number, since it uses as much as digits as its factorization.

231280921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45322.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 231280921 is about 15207.9229679796. The cubic root of 231280921 is about 613.8278694634.

The spelling of 231280921 in words is "two hundred thirty-one million, two hundred eighty thousand, nine hundred twenty-one".