81131704 has 8 divisors (see below), whose sum is σ = 152121960. Its totient is φ = 40565848.

The previous prime is 81131693. The next prime is 81131719. The reversal of 81131704 is 40713118.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5070724 + ... + 5070739.

It is an arithmetic number, because the mean of its divisors is an integer number (19015245).

Almost surely, 2^81131704 is an apocalyptic number.

It is an amenable number.

81131704 is a deficient number, since it is larger than the sum of its proper divisors (70990256).

81131704 is a wasteful number, since it uses less digits than its factorization.

81131704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10141469 (or 10141465 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 81131704 is about 9007.3139170343. The cubic root of 81131704 is about 432.9092503255.

The spelling of 81131704 in words is "eighty-one million, one hundred thirty-one thousand, seven hundred four".