81304543 has 4 divisors (see below), whose sum is σ = 81323248. Its totient is φ = 81285840.

The previous prime is 81304541. The next prime is 81304547. The reversal of 81304543 is 34540318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34540318 = 2 ⋅17270159.

It is a cyclic number.

It is not a de Polignac number, because 81304543 - 2¹ = 81304541 is a prime.

It is a super-2 number, since 2×81304543² = 13220857424877698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81304541) 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, 955 + ... + 12787.

It is an arithmetic number, because the mean of its divisors is an integer number (20330812).

Almost surely, 2^81304543 is an apocalyptic number.

81304543 is a deficient number, since it is larger than the sum of its proper divisors (18705).

81304543 is a wasteful number, since it uses less digits than its factorization.

81304543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18704.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 81304543 is about 9016.9031823570. The cubic root of 81304543 is about 433.2164484881.

The spelling of 81304543 in words is "eighty-one million, three hundred four thousand, five hundred forty-three".