81181584826 has 8 divisors (see below), whose sum is σ = 125971424820. Its totient is φ = 39191109888.

The previous prime is 81181584823. The next prime is 81181584839. The reversal of 81181584826 is 62848518118.

It can be written as a sum of positive squares in 2 ways, for example, as 76399724025 + 4781860801 = 276405^2 + 69151^2 .

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

It is a super-2 number, since 2×81181584826² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81181584823) 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, 699841191 + ... + 699841306.

Almost surely, 2^81181584826 is an apocalyptic number.

81181584826 is a deficient number, since it is larger than the sum of its proper divisors (44789839994).

81181584826 is a wasteful number, since it uses less digits than its factorization.

81181584826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1399682528.

The product of its digits is 983040, while the sum is 52.

The spelling of 81181584826 in words is "eighty-one billion, one hundred eighty-one million, five hundred eighty-four thousand, eight hundred twenty-six".