81332810 has 16 divisors (see below), whose sum is σ = 157660776. Its totient is φ = 30030528.

The previous prime is 81332759. The next prime is 81332813. The reversal of 81332810 is 1823318.

It can be written as a sum of positive squares in 4 ways, for example, as 57410929 + 23921881 = 7577^2 + 4891^2 .

It is a super-2 number, since 2×81332810² = 13230051964992200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81332810.

It is not an unprimeable number, because it can be changed into a prime (81332813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 312689 + ... + 312948.

Almost surely, 2^81332810 is an apocalyptic number.

81332810 is a deficient number, since it is larger than the sum of its proper divisors (76327966).

81332810 is a wasteful number, since it uses less digits than its factorization.

81332810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625657.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 81332810 is about 9018.4704911642. The cubic root of 81332810 is about 433.2666478580.

The spelling of 81332810 in words is "eighty-one million, three hundred thirty-two thousand, eight hundred ten".