81275717 has 4 divisors (see below), whose sum is σ = 83472396. Its totient is φ = 79079040.

The previous prime is 81275713. The next prime is 81275743. The reversal of 81275717 is 71757218.

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 77457601 + 3818116 = 8801^2 + 1954^2 .

It is a cyclic number.

It is not a de Polignac number, because 81275717 - 2² = 81275713 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81275713) 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, 1098284 + ... + 1098357.

It is an arithmetic number, because the mean of its divisors is an integer number (20868099).

Almost surely, 2^81275717 is an apocalyptic number.

It is an amenable number.

81275717 is a deficient number, since it is larger than the sum of its proper divisors (2196679).

81275717 is a wasteful number, since it uses less digits than its factorization.

81275717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2196678.

The product of its digits is 27440, while the sum is 38.

The square root of 81275717 is about 9015.3045982928. The cubic root of 81275717 is about 433.1652444061.

The spelling of 81275717 in words is "eighty-one million, two hundred seventy-five thousand, seven hundred seventeen".