81466531 has 4 divisors (see below), whose sum is σ = 81760912. Its totient is φ = 81172152.

The previous prime is 81466523. The next prime is 81466577. The reversal of 81466531 is 13566418.

It is a happy number.

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 81466531 - 2³ = 81466523 is a prime.

It is a super-2 number, since 2×81466531² = 13273591346347922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81466501) 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, 146775 + ... + 147328.

It is an arithmetic number, because the mean of its divisors is an integer number (20440228).

Almost surely, 2^81466531 is an apocalyptic number.

81466531 is a deficient number, since it is larger than the sum of its proper divisors (294381).

81466531 is a wasteful number, since it uses less digits than its factorization.

81466531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294380.

The product of its digits is 17280, while the sum is 34.

The square root of 81466531 is about 9025.8811758188. The cubic root of 81466531 is about 433.5039654778.

The spelling of 81466531 in words is "eighty-one million, four hundred sixty-six thousand, five hundred thirty-one".