81537443 has 8 divisors (see below), whose sum is σ = 88130448. Its totient is φ = 74990304.

The previous prime is 81537437. The next prime is 81537451. The reversal of 81537443 is 34473518.

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 81537443 - 2²⁰ = 80488867 is a prime.

It is a super-2 number, since 2×81537443² = 13296709221956498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81537403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7721 + ... + 14922.

It is an arithmetic number, because the mean of its divisors is an integer number (11016306).

Almost surely, 2^81537443 is an apocalyptic number.

81537443 is a deficient number, since it is larger than the sum of its proper divisors (6593005).

81537443 is a wasteful number, since it uses less digits than its factorization.

81537443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22933.

The product of its digits is 40320, while the sum is 35.

The square root of 81537443 is about 9029.8085804739. The cubic root of 81537443 is about 433.6297092150.

The spelling of 81537443 in words is "eighty-one million, five hundred thirty-seven thousand, four hundred forty-three".