81356541 has 16 divisors (see below), whose sum is σ = 124180608. Its totient is φ = 46411200.

The previous prime is 81356531. The next prime is 81356549. The reversal of 81356541 is 14565318.

It is not a de Polignac number, because 81356541 - 2¹⁵ = 81323773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81356549) 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 15 ways as a sum of consecutive naturals, for example, 10951 + ... + 16811.

It is an arithmetic number, because the mean of its divisors is an integer number (7761288).

Almost surely, 2^81356541 is an apocalyptic number.

It is an amenable number.

81356541 is a deficient number, since it is larger than the sum of its proper divisors (42824067).

81356541 is a wasteful number, since it uses less digits than its factorization.

81356541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6532.

The product of its digits is 14400, while the sum is 33.

The square root of 81356541 is about 9019.7860839379. The cubic root of 81356541 is about 433.3087827643.

The spelling of 81356541 in words is "eighty-one million, three hundred fifty-six thousand, five hundred forty-one".