231813109 has 4 divisors (see below), whose sum is σ = 252887040. Its totient is φ = 210739180.

The previous prime is 231813089. The next prime is 231813137. The reversal of 231813109 is 901318132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 231813109 - 2⁵ = 231813077 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 (231813209) 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, 10536949 + ... + 10536970.

It is an arithmetic number, because the mean of its divisors is an integer number (63221760).

Almost surely, 2^231813109 is an apocalyptic number.

It is an amenable number.

231813109 is a deficient number, since it is larger than the sum of its proper divisors (21073931).

231813109 is a wasteful number, since it uses less digits than its factorization.

231813109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21073930.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 231813109 is about 15225.4099780597. The cubic root of 231813109 is about 614.2983241559.

The spelling of 231813109 in words is "two hundred thirty-one million, eight hundred thirteen thousand, one hundred nine".