81311727 has 12 divisors (see below), whose sum is σ = 126116376. Its totient is φ = 46463760.

The previous prime is 81311723. The next prime is 81311743. The reversal of 81311727 is 72711318.

It is not a de Polignac number, because 81311727 - 2² = 81311723 is a prime.

It is a super-2 number, since 2×81311727² = 13223193895445058, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81311694 and 81311703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81311723) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 276424 + ... + 276717.

It is an arithmetic number, because the mean of its divisors is an integer number (10509698).

Almost surely, 2^81311727 is an apocalyptic number.

81311727 is a deficient number, since it is larger than the sum of its proper divisors (44804649).

81311727 is a wasteful number, since it uses less digits than its factorization.

81311727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553158 (or 553151 counting only the distinct ones).

The product of its digits is 2352, while the sum is 30.

The square root of 81311727 is about 9017.3015364908. The cubic root of 81311727 is about 433.2292076575.

The spelling of 81311727 in words is "eighty-one million, three hundred eleven thousand, seven hundred twenty-seven".