81658543 has 4 divisors (see below), whose sum is σ = 81755128. Its totient is φ = 81561960.

The previous prime is 81658541. The next prime is 81658567. The reversal of 81658543 is 34585618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34585618 = 2 ⋅17292809.

It is a cyclic number.

It is not a de Polignac number, because 81658543 - 2¹ = 81658541 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81658496 and 81658505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81658541) 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, 47013 + ... + 48718.

It is an arithmetic number, because the mean of its divisors is an integer number (20438782).

Almost surely, 2^81658543 is an apocalyptic number.

81658543 is a deficient number, since it is larger than the sum of its proper divisors (96585).

81658543 is an equidigital number, since it uses as much as digits as its factorization.

81658543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96584.

The product of its digits is 115200, while the sum is 40.

The square root of 81658543 is about 9036.5116610338. The cubic root of 81658543 is about 433.8442796828.

The spelling of 81658543 in words is "eighty-one million, six hundred fifty-eight thousand, five hundred forty-three".