81455505 has 8 divisors (see below), whose sum is σ = 130328832. Its totient is φ = 43442928.

The previous prime is 81455467. The next prime is 81455509. The reversal of 81455505 is 50555418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81455505 - 2⁶ = 81455441 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81455509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2715169 + ... + 2715198.

It is an arithmetic number, because the mean of its divisors is an integer number (16291104).

Almost surely, 2^81455505 is an apocalyptic number.

It is an amenable number.

81455505 is a deficient number, since it is larger than the sum of its proper divisors (48873327).

81455505 is a wasteful number, since it uses less digits than its factorization.

81455505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5430375.

The product of its (nonzero) digits is 20000, while the sum is 33.

The square root of 81455505 is about 9025.2703560614. The cubic root of 81455505 is about 433.4844072195.

The spelling of 81455505 in words is "eighty-one million, four hundred fifty-five thousand, five hundred five".