181312505 has 16 divisors (see below), whose sum is σ = 240364800. Its totient is φ = 130191360.

The previous prime is 181312493. The next prime is 181312541. The reversal of 181312505 is 505213181.

It is a happy number.

It is not a de Polignac number, because 181312505 - 2¹⁴ = 181296121 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16520 + ... + 25209.

It is an arithmetic number, because the mean of its divisors is an integer number (15022800).

Almost surely, 2^181312505 is an apocalyptic number.

It is an amenable number.

181312505 is a deficient number, since it is larger than the sum of its proper divisors (59052295).

181312505 is a wasteful number, since it uses less digits than its factorization.

181312505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41824.

The product of its (nonzero) digits is 1200, while the sum is 26.

The square root of 181312505 is about 13465.2331951586. The cubic root of 181312505 is about 565.9906446280.

Adding to 181312505 its reverse (505213181), we get a palindrome (686525686).

The spelling of 181312505 in words is "one hundred eighty-one million, three hundred twelve thousand, five hundred five".