81144099810 has 40 divisors (see below), whose sum is σ = 218187470556. Its totient is φ = 21638426400.

The previous prime is 81144099809. The next prime is 81144099833. The reversal of 81144099810 is 1899044118.

It can be written as a sum of positive squares in 2 ways, for example, as 76625436969 + 4518662841 = 276813^2 + 67221^2 .

It is a super-2 number, since 2×81144099810² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 50088141 + ... + 50089760.

Almost surely, 2^81144099810 is an apocalyptic number.

81144099810 is an abundant number, since it is smaller than the sum of its proper divisors (137043370746).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81144099810 is a wasteful number, since it uses less digits than its factorization.

81144099810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100177920 (or 100177911 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The spelling of 81144099810 in words is "eighty-one billion, one hundred forty-four million, ninety-nine thousand, eight hundred ten".