81408733541 has 4 divisors (see below), whose sum is σ = 81468550284. Its totient is φ = 81348916800.

The previous prime is 81408733531. The next prime is 81408733559. The reversal of 81408733541 is 14533780418.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 57242476516 + 24166257025 = 239254^2 + 155455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81408733541 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81408733492 and 81408733501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81408733531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29906330 + ... + 29909051.

It is an arithmetic number, because the mean of its divisors is an integer number (20367137571).

Almost surely, 2^81408733541 is an apocalyptic number.

It is an amenable number.

81408733541 is a deficient number, since it is larger than the sum of its proper divisors (59816743).

81408733541 is a wasteful number, since it uses less digits than its factorization.

81408733541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59816742.

The product of its (nonzero) digits is 322560, while the sum is 44.

The spelling of 81408733541 in words is "eighty-one billion, four hundred eight million, seven hundred thirty-three thousand, five hundred forty-one".