231772509 has 30 divisors (see below), whose sum is σ = 367829594. Its totient is φ = 145411200.

The previous prime is 231772481. The next prime is 231772511. The reversal of 231772509 is 905277132.

231772509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 159896025 + 71876484 = 12645^2 + 8478^2 .

It is not a de Polignac number, because 231772509 - 2⁷ = 231772381 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 (231772589) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 18459 + ... + 28359.

Almost surely, 2^231772509 is an apocalyptic number.

It is an amenable number.

231772509 is a deficient number, since it is larger than the sum of its proper divisors (136057085).

231772509 is an equidigital number, since it uses as much as digits as its factorization.

231772509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9947 (or 9921 counting only the distinct ones).

The product of its (nonzero) digits is 26460, while the sum is 36.

The square root of 231772509 is about 15224.0766222454. The cubic root of 231772509 is about 614.2624591032.

The spelling of 231772509 in words is "two hundred thirty-one million, seven hundred seventy-two thousand, five hundred nine".