81815715145 has 8 divisors (see below), whose sum is σ = 98619123456. Its totient is φ = 65159061936.

The previous prime is 81815715143. The next prime is 81815715181. The reversal of 81815715145 is 54151751818.

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 81815715145 - 2¹ = 81815715143 is a prime.

It is a super-2 number, since 2×81815715145² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81815715095 and 81815715104.

It is not an unprimeable number, because it can be changed into a prime (81815715143) 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 7 ways as a sum of consecutive naturals, for example, 36687547 + ... + 36689776.

It is an arithmetic number, because the mean of its divisors is an integer number (12327390432).

Almost surely, 2^81815715145 is an apocalyptic number.

It is an amenable number.

81815715145 is a deficient number, since it is larger than the sum of its proper divisors (16803408311).

81815715145 is a wasteful number, since it uses less digits than its factorization.

81815715145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73377551.

The product of its digits is 224000, while the sum is 46.

The spelling of 81815715145 in words is "eighty-one billion, eight hundred fifteen million, seven hundred fifteen thousand, one hundred forty-five".