81768825 has 24 divisors (see below), whose sum is σ = 150213600. Its totient is φ = 43609680.

The previous prime is 81768803. The next prime is 81768829. The reversal of 81768825 is 52886718.

It is not a de Polignac number, because 81768825 - 2⁷ = 81768697 is a prime.

It is a super-2 number, since 2×81768825² = 13372281483761250, which contains 22 as substring.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81768829) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 59895 + ... + 61244.

It is an arithmetic number, because the mean of its divisors is an integer number (6258900).

Almost surely, 2^81768825 is an apocalyptic number.

It is an amenable number.

81768825 is a deficient number, since it is larger than the sum of its proper divisors (68444775).

81768825 is a wasteful number, since it uses less digits than its factorization.

81768825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121158 (or 121147 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 81768825 is about 9042.6116249676. The cubic root of 81768825 is about 434.0394978458.

The spelling of 81768825 in words is "eighty-one million, seven hundred sixty-eight thousand, eight hundred twenty-five".