81455329 has 4 divisors (see below), whose sum is σ = 82992276. Its totient is φ = 79918384.

The previous prime is 81455323. The next prime is 81455393. The reversal of 81455329 is 92355418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 92355418 = 2 ⋅46177709.

It can be written as a sum of positive squares in 2 ways, for example, as 72165025 + 9290304 = 8495^2 + 3048^2 .

It is a cyclic number.

It is not a de Polignac number, because 81455329 - 2⁹ = 81454817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81455323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 768394 + ... + 768499.

It is an arithmetic number, because the mean of its divisors is an integer number (20748069).

Almost surely, 2^81455329 is an apocalyptic number.

It is an amenable number.

81455329 is a deficient number, since it is larger than the sum of its proper divisors (1536947).

81455329 is a wasteful number, since it uses less digits than its factorization.

81455329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536946.

The product of its digits is 43200, while the sum is 37.

The square root of 81455329 is about 9025.2606056557. The cubic root of 81455329 is about 433.4840950110.

The spelling of 81455329 in words is "eighty-one million, four hundred fifty-five thousand, three hundred twenty-nine".