81527731 has 4 divisors (see below), whose sum is σ = 81887112. Its totient is φ = 81168352.

The previous prime is 81527707. The next prime is 81527753. The reversal of 81527731 is 13772518.

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

It is a cyclic number.

It is not a de Polignac number, because 81527731 - 2⁷ = 81527603 is a prime.

It is a super-2 number, since 2×81527731² = 13293541844016722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81527701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179350 + ... + 179803.

It is an arithmetic number, because the mean of its divisors is an integer number (20471778).

Almost surely, 2^81527731 is an apocalyptic number.

81527731 is a deficient number, since it is larger than the sum of its proper divisors (359381).

81527731 is a wasteful number, since it uses less digits than its factorization.

81527731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359380.

The product of its digits is 11760, while the sum is 34.

The square root of 81527731 is about 9029.2707900472. The cubic root of 81527731 is about 433.6124918532.

The spelling of 81527731 in words is "eighty-one million, five hundred twenty-seven thousand, seven hundred thirty-one".