81465571 has 4 divisors (see below), whose sum is σ = 88871544. Its totient is φ = 74059600.

The previous prime is 81465541. The next prime is 81465577. The reversal of 81465571 is 17556418.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81465571 - 2⁵ = 81465539 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81465571.

It is not an unprimeable number, because it can be changed into a prime (81465577) 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, 3702970 + ... + 3702991.

It is an arithmetic number, because the mean of its divisors is an integer number (22217886).

Almost surely, 2^81465571 is an apocalyptic number.

81465571 is a deficient number, since it is larger than the sum of its proper divisors (7405973).

81465571 is a wasteful number, since it uses less digits than its factorization.

81465571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7405972.

The product of its digits is 33600, while the sum is 37.

The square root of 81465571 is about 9025.8279952589. The cubic root of 81465571 is about 433.5022626704.

It can be divided in two parts, 814655 and 71, that added together give a triangular number (814726 = T₁₂₇₆).

The spelling of 81465571 in words is "eighty-one million, four hundred sixty-five thousand, five hundred seventy-one".