231213561 has 8 divisors (see below), whose sum is σ = 308357280. Its totient is φ = 154106112.

The previous prime is 231213551. The next prime is 231213571. The reversal of 231213561 is 165312132.

231213561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (231213551) and next prime (231213571).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 231213561 - 2⁶ = 231213497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (231213551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14745 + ... + 26073.

It is an arithmetic number, because the mean of its divisors is an integer number (38544660).

Almost surely, 2^231213561 is an apocalyptic number.

It is an amenable number.

231213561 is a deficient number, since it is larger than the sum of its proper divisors (77143719).

231213561 is a wasteful number, since it uses less digits than its factorization.

231213561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18135.

The product of its digits is 1080, while the sum is 24.

The square root of 231213561 is about 15205.7081716045. The cubic root of 231213561 is about 613.7682717241.

Adding to 231213561 its reverse (165312132), we get a palindrome (396525693).

The spelling of 231213561 in words is "two hundred thirty-one million, two hundred thirteen thousand, five hundred sixty-one".