81212571492 has 72 divisors (see below), whose sum is σ = 215378726976. Its totient is φ = 23673283776.

The previous prime is 81212571481. The next prime is 81212571527. The reversal of 81212571492 is 29417521218.

It is a super-2 number, since 2×81212571492² (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 23 ways as a sum of consecutive naturals, for example, 664728 + ... + 777359.

It is an arithmetic number, because the mean of its divisors is an integer number (2991371208).

Almost surely, 2^81212571492 is an apocalyptic number.

It is an amenable number.

81212571492 is an abundant number, since it is smaller than the sum of its proper divisors (134166155484).

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

81212571492 is a wasteful number, since it uses less digits than its factorization.

81212571492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442145 (or 1442124 counting only the distinct ones).

The product of its digits is 80640, while the sum is 42.

The spelling of 81212571492 in words is "eighty-one billion, two hundred twelve million, five hundred seventy-one thousand, four hundred ninety-two".