81811053 has 12 divisors (see below), whose sum is σ = 122548608. Its totient is φ = 54540540.

The previous prime is 81811039. The next prime is 81811073. The reversal of 81811053 is 35011818.

It is not a de Polignac number, because 81811053 - 2²⁶ = 14702189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81811003) 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 11 ways as a sum of consecutive naturals, for example, 168093 + ... + 168578.

It is an arithmetic number, because the mean of its divisors is an integer number (10212384).

Almost surely, 2^81811053 is an apocalyptic number.

It is an amenable number.

81811053 is a deficient number, since it is larger than the sum of its proper divisors (40737555).

81811053 is an equidigital number, since it uses as much as digits as its factorization.

81811053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336686 (or 336674 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 81811053 is about 9044.9462684971. The cubic root of 81811053 is about 434.1142022157.

The spelling of 81811053 in words is "eighty-one million, eight hundred eleven thousand, fifty-three".