81506076521072 has 20 divisors (see below), whose sum is σ = 180477740868336. Its totient is φ = 34931175651840.

The previous prime is 81506076520991. The next prime is 81506076521087. The reversal of 81506076521072 is 27012567060518.

It is a super-3 number, since 3×81506076521072³ (a number of 43 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81506076521072.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363866412929 + ... + 363866413152.

Almost surely, 2^{81506076521072} is an apocalyptic number.

It is an amenable number.

81506076521072 is an abundant number, since it is smaller than the sum of its proper divisors (98971664347264).

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

81506076521072 is a wasteful number, since it uses less digits than its factorization.

81506076521072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727732826096 (or 727732826090 counting only the distinct ones).

The product of its (nonzero) digits is 1411200, while the sum is 50.

The spelling of 81506076521072 in words is "eighty-one trillion, five hundred six billion, seventy-six million, five hundred twenty-one thousand, seventy-two".