81270505 has 16 divisors (see below), whose sum is σ = 104112000. Its totient is φ = 60721920.

The previous prime is 81270491. The next prime is 81270521. The reversal of 81270505 is 50507218.

It is not a de Polignac number, because 81270505 - 2⁷ = 81270377 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 721 + ... + 12769.

It is an arithmetic number, because the mean of its divisors is an integer number (6507000).

Almost surely, 2^81270505 is an apocalyptic number.

It is an amenable number.

81270505 is a deficient number, since it is larger than the sum of its proper divisors (22841495).

81270505 is a wasteful number, since it uses less digits than its factorization.

81270505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12144.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 81270505 is about 9015.0155296594. The cubic root of 81270505 is about 433.1559849553.

It can be divided in two parts, 812 and 70505, that added together give a palindrome (71317).

The spelling of 81270505 in words is "eighty-one million, two hundred seventy thousand, five hundred five".