81816265 has 4 divisors (see below), whose sum is σ = 98179524. Its totient is φ = 65453008.

The previous prime is 81816239. The next prime is 81816269. The reversal of 81816265 is 56261818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20178064 + 61638201 = 4492^2 + 7851^2 .

It is a cyclic number.

It is not a de Polignac number, because 81816265 - 2⁵ = 81816233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81816269) 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, 8181622 + ... + 8181631.

It is an arithmetic number, because the mean of its divisors is an integer number (24544881).

Almost surely, 2^81816265 is an apocalyptic number.

It is an amenable number.

81816265 is a deficient number, since it is larger than the sum of its proper divisors (16363259).

81816265 is a wasteful number, since it uses less digits than its factorization.

81816265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16363258.

The product of its digits is 23040, while the sum is 37.

The square root of 81816265 is about 9045.2343806006. The cubic root of 81816265 is about 434.1234208363.

The spelling of 81816265 in words is "eighty-one million, eight hundred sixteen thousand, two hundred sixty-five".