81425543 has 8 divisors (see below), whose sum is σ = 86570208. Its totient is φ = 76414624.

The previous prime is 81425521. The next prime is 81425599. The reversal of 81425543 is 34552418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81425543 - 2¹⁸ = 81163399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81427543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32180 + ... + 34617.

It is an arithmetic number, because the mean of its divisors is an integer number (10821276).

Almost surely, 2^81425543 is an apocalyptic number.

81425543 is a deficient number, since it is larger than the sum of its proper divisors (5144665).

81425543 is a wasteful number, since it uses less digits than its factorization.

81425543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66873.

The product of its digits is 19200, while the sum is 32.

The square root of 81425543 is about 9023.6103085184. The cubic root of 81425543 is about 433.4312507851.

The spelling of 81425543 in words is "eighty-one million, four hundred twenty-five thousand, five hundred forty-three".