231513215 has 4 divisors (see below), whose sum is σ = 277815864. Its totient is φ = 185210568.

The previous prime is 231513199. The next prime is 231513221. The reversal of 231513215 is 512315132.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 231513215 - 2⁴ = 231513199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23151317 + ... + 23151326.

It is an arithmetic number, because the mean of its divisors is an integer number (69453966).

Almost surely, 2^231513215 is an apocalyptic number.

231513215 is a deficient number, since it is larger than the sum of its proper divisors (46302649).

231513215 is an equidigital number, since it uses as much as digits as its factorization.

231513215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46302648.

The product of its digits is 900, while the sum is 23.

The square root of 231513215 is about 15215.5583203509. The cubic root of 231513215 is about 614.0333062390.

Adding to 231513215 its reverse (512315132), we get a palindrome (743828347).

The spelling of 231513215 in words is "two hundred thirty-one million, five hundred thirteen thousand, two hundred fifteen".