81995331385 has 32 divisors (see below), whose sum is σ = 107711856000. Its totient is φ = 59426357760.

The previous prime is 81995331331. The next prime is 81995331391. The reversal of 81995331385 is 58313359918.

It is not a de Polignac number, because 81995331385 - 2¹⁵ = 81995298617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35695557 + ... + 35697853.

It is an arithmetic number, because the mean of its divisors is an integer number (3365995500).

Almost surely, 2^81995331385 is an apocalyptic number.

It is an amenable number.

81995331385 is a deficient number, since it is larger than the sum of its proper divisors (25716524615).

81995331385 is a wasteful number, since it uses less digits than its factorization.

81995331385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4281.

The product of its digits is 3499200, while the sum is 55.

The spelling of 81995331385 in words is "eighty-one billion, nine hundred ninety-five million, three hundred thirty-one thousand, three hundred eighty-five".