81521175316 has 24 divisors (see below), whose sum is σ = 163429648256. Its totient is φ = 34854654240.

The previous prime is 81521175313. The next prime is 81521175343. The reversal of 81521175316 is 61357112518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81521175311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3446016 + ... + 3469591.

Almost surely, 2^81521175316 is an apocalyptic number.

It is an amenable number.

81521175316 is an abundant number, since it is smaller than the sum of its proper divisors (81908472940).

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

81521175316 is a wasteful number, since it uses less digits than its factorization.

81521175316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6916039 (or 6916037 counting only the distinct ones).

The product of its digits is 50400, while the sum is 40.

The spelling of 81521175316 in words is "eighty-one billion, five hundred twenty-one million, one hundred seventy-five thousand, three hundred sixteen".