81811426 has 12 divisors (see below), whose sum is σ = 123538662. Its totient is φ = 40632944.

The previous prime is 81811417. The next prime is 81811427. The reversal of 81811426 is 62411818.

It can be written as a sum of positive squares in only one way, i.e., 77422401 + 4389025 = 8799^2 + 2095^2 .

It is not an unprimeable number, because it can be changed into a prime (81811427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 195045 + ... + 195463.

Almost surely, 2^81811426 is an apocalyptic number.

81811426 is a deficient number, since it is larger than the sum of its proper divisors (41727236).

81811426 is an equidigital number, since it uses as much as digits as its factorization.

81811426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073 (or 654 counting only the distinct ones).

The product of its digits is 3072, while the sum is 31.

The square root of 81811426 is about 9044.9668877227. The cubic root of 81811426 is about 434.1148619650.

The spelling of 81811426 in words is "eighty-one million, eight hundred eleven thousand, four hundred twenty-six".