231515221135 has 24 divisors (see below), whose sum is σ = 307392932448. Its totient is φ = 167259576000.

The previous prime is 231515221127. The next prime is 231515221153. The reversal of 231515221135 is 531122515132.

It is a happy number.

It is not a de Polignac number, because 231515221135 - 2³ = 231515221127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231515221097 and 231515221106.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1175764 + ... + 1358473.

It is an arithmetic number, because the mean of its divisors is an integer number (12808038852).

Almost surely, 2^231515221135 is an apocalyptic number.

231515221135 is a deficient number, since it is larger than the sum of its proper divisors (75877711313).

231515221135 is a wasteful number, since it uses less digits than its factorization.

231515221135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2534415 (or 2534404 counting only the distinct ones).

The product of its digits is 9000, while the sum is 31.

Adding to 231515221135 its reverse (531122515132), we get a palindrome (762637736267).

The spelling of 231515221135 in words is "two hundred thirty-one billion, five hundred fifteen million, two hundred twenty-one thousand, one hundred thirty-five".