81875065 has 4 divisors (see below), whose sum is σ = 98250084. Its totient is φ = 65500048.

The previous prime is 81875021. The next prime is 81875071. The reversal of 81875065 is 56057818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56057818 = 2 ⋅28028909.

It can be written as a sum of positive squares in 2 ways, for example, as 62267881 + 19607184 = 7891^2 + 4428^2 .

It is a cyclic number.

It is not a de Polignac number, because 81875065 - 2¹⁹ = 81350777 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8187502 + ... + 8187511.

It is an arithmetic number, because the mean of its divisors is an integer number (24562521).

Almost surely, 2^81875065 is an apocalyptic number.

It is an amenable number.

81875065 is a deficient number, since it is larger than the sum of its proper divisors (16375019).

81875065 is a wasteful number, since it uses less digits than its factorization.

81875065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16375018.

The product of its (nonzero) digits is 67200, while the sum is 40.

The square root of 81875065 is about 9048.4841271895. The cubic root of 81875065 is about 434.2273950458.

The spelling of 81875065 in words is "eighty-one million, eight hundred seventy-five thousand, sixty-five".