665215131 has 24 divisors (see below), whose sum is σ = 1076626944. Its totient is φ = 363594000.

The previous prime is 665215129. The next prime is 665215157. The reversal of 665215131 is 131512566.

665215131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 665215131 - 2¹ = 665215129 is a prime.

It is a super-2 number, since 2×665215131² = 885022341022694322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665215121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 94995 + ... + 101756.

It is an arithmetic number, because the mean of its divisors is an integer number (44859456).

Almost surely, 2^665215131 is an apocalyptic number.

665215131 is a deficient number, since it is larger than the sum of its proper divisors (411411813).

665215131 is a wasteful number, since it uses less digits than its factorization.

665215131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196791 (or 196784 counting only the distinct ones).

The product of its digits is 5400, while the sum is 30.

The square root of 665215131 is about 25791.7647903357. The cubic root of 665215131 is about 872.9459874289.

Adding to 665215131 its reverse (131512566), we get a palindrome (796727697).

The spelling of 665215131 in words is "six hundred sixty-five million, two hundred fifteen thousand, one hundred thirty-one".