231528561 has 8 divisors (see below), whose sum is σ = 336768864. Its totient is φ = 140320320.

The previous prime is 231528551. The next prime is 231528571. The reversal of 231528561 is 165825132.

It is an interprime number because it is at equal distance from previous prime (231528551) and next prime (231528571).

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

It is not a de Polignac number, because 231528561 - 2⁶ = 231528497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 7016017 = 231528561 / (2 + 3 + 1 + 5 + 2 + 8 + 5 + 6 + 1).

It is not an unprimeable number, because it can be changed into a prime (231528541) 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, 3507976 + ... + 3508041.

It is an arithmetic number, because the mean of its divisors is an integer number (42096108).

Almost surely, 2^231528561 is an apocalyptic number.

It is an amenable number.

231528561 is a deficient number, since it is larger than the sum of its proper divisors (105240303).

231528561 is a wasteful number, since it uses less digits than its factorization.

231528561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7016031.

The product of its digits is 14400, while the sum is 33.

The square root of 231528561 is about 15216.0625984517. The cubic root of 231528561 is about 614.0468731347.

It can be divided in two parts, 23152 and 8561, that added together give a palindrome (31713).

The spelling of 231528561 in words is "two hundred thirty-one million, five hundred twenty-eight thousand, five hundred sixty-one".