81145997492 has 24 divisors (see below), whose sum is σ = 162300008640. Its totient is φ = 34775138880.

The previous prime is 81145997467. The next prime is 81145997561. The reversal of 81145997492 is 29479954118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 624392 + ... + 743072.

It is an arithmetic number, because the mean of its divisors is an integer number (6762500360).

Almost surely, 2^81145997492 is an apocalyptic number.

It is an amenable number.

81145997492 is an abundant number, since it is smaller than the sum of its proper divisors (81154011148).

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

81145997492 is a wasteful number, since it uses less digits than its factorization.

81145997492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143111 (or 143109 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 59.

The spelling of 81145997492 in words is "eighty-one billion, one hundred forty-five million, nine hundred ninety-seven thousand, four hundred ninety-two".