231228661 has 4 divisors (see below), whose sum is σ = 231272172. Its totient is φ = 231185152.

The previous prime is 231228649. The next prime is 231228677. The reversal of 231228661 is 166822132.

231228661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 180391761 + 50836900 = 13431^2 + 7130^2 .

It is a cyclic number.

It is not a de Polignac number, because 231228661 - 2⁷ = 231228533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231228601) 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, 12460 + ... + 24853.

It is an arithmetic number, because the mean of its divisors is an integer number (57818043).

Almost surely, 2^231228661 is an apocalyptic number.

It is an amenable number.

231228661 is a deficient number, since it is larger than the sum of its proper divisors (43511).

231228661 is an equidigital number, since it uses as much as digits as its factorization.

231228661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43510.

The product of its digits is 6912, while the sum is 31.

The square root of 231228661 is about 15206.2046875609. The cubic root of 231228661 is about 613.7816326751.

The spelling of 231228661 in words is "two hundred thirty-one million, two hundred twenty-eight thousand, six hundred sixty-one".