81465217 has 4 divisors (see below), whose sum is σ = 85752880. Its totient is φ = 77177556.

The previous prime is 81465119. The next prime is 81465221. The reversal of 81465217 is 71256418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81465217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81462217) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2143803 + ... + 2143840.

It is an arithmetic number, because the mean of its divisors is an integer number (21438220).

Almost surely, 2^81465217 is an apocalyptic number.

It is an amenable number.

81465217 is a deficient number, since it is larger than the sum of its proper divisors (4287663).

81465217 is a wasteful number, since it uses less digits than its factorization.

81465217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4287662.

The product of its digits is 13440, while the sum is 34.

The square root of 81465217 is about 9025.8083848484. The cubic root of 81465217 is about 433.5016347568.

The spelling of 81465217 in words is "eighty-one million, four hundred sixty-five thousand, two hundred seventeen".