81681188148 has 72 divisors (see below), whose sum is σ = 236505709440. Its totient is φ = 23284290240.

The previous prime is 81681188143. The next prime is 81681188177. The reversal of 81681188148 is 84188118618.

It is a happy number.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81681188094 and 81681188103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81681188143) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 258543 + ... + 479798.

It is an arithmetic number, because the mean of its divisors is an integer number (3284801520).

Almost surely, 2^81681188148 is an apocalyptic number.

It is an amenable number.

81681188148 is an abundant number, since it is smaller than the sum of its proper divisors (154824521292).

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

81681188148 is a wasteful number, since it uses less digits than its factorization.

81681188148 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738797 (or 738792 counting only the distinct ones).

The product of its digits is 786432, while the sum is 54.

The spelling of 81681188148 in words is "eighty-one billion, six hundred eighty-one million, one hundred eighty-eight thousand, one hundred forty-eight".