81645341 has 4 divisors (see below), whose sum is σ = 81714972. Its totient is φ = 81575712.

The previous prime is 81645323. The next prime is 81645349. The reversal of 81645341 is 14354618.

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

It can be written as a sum of positive squares in 2 ways, for example, as 45091225 + 36554116 = 6715^2 + 6046^2 .

It is a cyclic number.

It is not a de Polignac number, because 81645341 - 2²⁶ = 14536477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81645298 and 81645307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81645349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33026 + ... + 35411.

It is an arithmetic number, because the mean of its divisors is an integer number (20428743).

Almost surely, 2^81645341 is an apocalyptic number.

It is an amenable number.

81645341 is a deficient number, since it is larger than the sum of its proper divisors (69631).

81645341 is a wasteful number, since it uses less digits than its factorization.

81645341 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69630.

The product of its digits is 11520, while the sum is 32.

The square root of 81645341 is about 9035.7811505149. The cubic root of 81645341 is about 433.8208980881.

Adding to 81645341 its reverse (14354618), we get a palindrome (95999959).

The spelling of 81645341 in words is "eighty-one million, six hundred forty-five thousand, three hundred forty-one".