81211711724 has 96 divisors (see below), whose sum is σ = 174367420416. Its totient is φ = 32566913280.

The previous prime is 81211711709. The next prime is 81211711733. The reversal of 81211711724 is 42711711218.

It is a super-2 number, since 2×81211711724² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29033894 + ... + 29036690.

It is an arithmetic number, because the mean of its divisors is an integer number (1816327296).

Almost surely, 2^81211711724 is an apocalyptic number.

It is an amenable number.

81211711724 is an abundant number, since it is smaller than the sum of its proper divisors (93155708692).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81211711724 is a wasteful number, since it uses less digits than its factorization.

81211711724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5055 (or 5053 counting only the distinct ones).

The product of its digits is 6272, while the sum is 35.

The spelling of 81211711724 in words is "eighty-one billion, two hundred eleven million, seven hundred eleven thousand, seven hundred twenty-four".