181420505 has 16 divisors (see below), whose sum is σ = 249400704. Its totient is φ = 124104960.

The previous prime is 181420501. The next prime is 181420507. The reversal of 181420505 is 505024181.

It is not a de Polignac number, because 181420505 - 2² = 181420501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (181420501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9170 + ... + 21140.

It is an arithmetic number, because the mean of its divisors is an integer number (15587544).

Almost surely, 2^181420505 is an apocalyptic number.

It is an amenable number.

181420505 is a deficient number, since it is larger than the sum of its proper divisors (67980199).

181420505 is a wasteful number, since it uses less digits than its factorization.

181420505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12416.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 181420505 is about 13469.2429260148. The cubic root of 181420505 is about 566.1030010202.

Adding to 181420505 its reverse (505024181), we get a palindrome (686444686).

The spelling of 181420505 in words is "one hundred eighty-one million, four hundred twenty thousand, five hundred five".