81736170541 has 4 divisors (see below), whose sum is σ = 83278362492. Its totient is φ = 80193978592.

The previous prime is 81736170539. The next prime is 81736170563. The reversal of 81736170541 is 14507163718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14507163718 = 2 ⋅7253581859.

It can be written as a sum of positive squares in 2 ways, for example, as 62123568516 + 19612602025 = 249246^2 + 140045^2 .

It is a cyclic number.

It is not a de Polignac number, because 81736170541 - 2¹ = 81736170539 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 (81736170041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 771095896 + ... + 771096001.

It is an arithmetic number, because the mean of its divisors is an integer number (20819590623).

Almost surely, 2^81736170541 is an apocalyptic number.

It is an amenable number.

81736170541 is a deficient number, since it is larger than the sum of its proper divisors (1542191951).

81736170541 is a wasteful number, since it uses less digits than its factorization.

81736170541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542191950.

The product of its (nonzero) digits is 141120, while the sum is 43.

The spelling of 81736170541 in words is "eighty-one billion, seven hundred thirty-six million, one hundred seventy thousand, five hundred forty-one".