81381684541 has 8 divisors (see below), whose sum is σ = 83130485760. Its totient is φ = 79633603248.

The previous prime is 81381684533. The next prime is 81381684547. The reversal of 81381684541 is 14548618318.

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

It is not a de Polignac number, because 81381684541 - 2³ = 81381684533 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 (81381684547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51700 + ... + 406738.

It is an arithmetic number, because the mean of its divisors is an integer number (10391310720).

Almost surely, 2^81381684541 is an apocalyptic number.

It is an amenable number.

81381684541 is a deficient number, since it is larger than the sum of its proper divisors (1748801219).

81381684541 is a wasteful number, since it uses less digits than its factorization.

81381684541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359963.

The product of its digits is 737280, while the sum is 49.

The spelling of 81381684541 in words is "eighty-one billion, three hundred eighty-one million, six hundred eighty-four thousand, five hundred forty-one".